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This free study is part of a 10 part series called "War Against Satan and Demons". To view more free studies in this series, click here.

10. Only by Prayer and Fasting

The War Against Satan and Demons


As we come to the passage we are studying today; we are reminded that Jesus taught the disciples how to minister in power to heal the sick and cast out demons. They had gone out in groups of two to do the works of the kingdom (Luke 9:1-6). At this stage in their training, Christ is preparing them for His departure from this world back to the Father, but when Jesus comes down from the Mount of Transfiguration with three of the disciples, the other nine disciples had encountered a tragic situation of a demonized boy. As Jesus approached the demonized boy, He saw that the disciples still lacked faith and power in God:


14When they came to the other disciples, they saw a large crowd around them and the teachers of the law arguing with them. 15As soon as all the people saw Jesus, they were overwhelmed with wonder and ran to greet him. 16"What are you arguing with them about?" he asked. 17A man in the crowd answered, "Teacher, I brought you my son, who is possessed by a spirit that has robbed him of speech. 18Whenever it seizes him, it throws him to the ground. He foams at the mouth, gnashes his teeth and becomes rigid. I asked your disciples to drive out the spirit, but they could not." 19"O unbelieving generation," Jesus replied, "how long shall I stay with you? How long shall I put up with you? Bring the boy to me." 20So they brought him. When the spirit saw Jesus, it immediately threw the boy into a convulsion. He fell to the ground and rolled around, foaming at the mouth. 21Jesus asked the boy's father, "How long has he been like this?" "From childhood," he answered. 22"It has often thrown him into fire or water to kill him. But if you can do anything, take pity on us and help us." 23" 'If you can'?" said Jesus. "Everything is possible for him who believes." 24Immediately the boy's father exclaimed, "I do believe; help me overcome my unbelief!" 25When Jesus saw that a crowd was running to the scene, he rebuked the evil spirit. "You deaf and mute spirit," he said, "I command you, come out of him and never enter him again." 26The spirit shrieked, convulsed him violently and came out. The boy looked so much like a corpse that many said, "He's dead." 27But Jesus took him by the hand and lifted him to his feet, and he stood up. 28After Jesus had gone indoors, his disciples asked him privately, "Why couldn't we drive it out?" 29He replied, "This kind can come out only by prayer” (Mark 9:14-29).


The disciples were powerless and lacked the faith to minister to a man’s son. In this case, Jesus said it was a demonic spirit that was destroying the boy's life.


In your own words, describe what you are seeing and hearing as if you were one of the onlookers. How would the medical establishment treat this scene today?


  1. The boy cannot speak due to the spirit controlling his vocal cords (v. 17).
  2. The spirit is seizing him at times and throwing him to the ground (v. 18).
  3. He is grinding or gnashing his teeth, and his whole body becomes rigid and foams at the mouth (v. 18).
  4. As soon as the spirit in the boy saw Jesus, he begins a new convulsion in the boy and rolls him around foaming at the mouth (v. 20).
  5. The father confesses that the boy has been like this since childhood. He cannot ever leave him alone because the spirit tries to kill him by making him throw himself into fire or water, perhaps into a cistern, a well or river seeking to drown him.


The boy was not in sight but was brought to Jesus. There was a visible manifestation as soon as the demonized boy came into the presence of Jesus. Mark tells us, “When the spirit saw Jesus, it immediately threw the boy into a convulsion. He fell to the ground and rolled around, foaming at the mouth” (Mark 9:20). Mark gives us additional information by saying that Jesus asked questions about the boy's condition (Mark 9:21). It is always good to ask questions in a ministry prayer session. Often, we can gain vital clues as to how to pray by finding out how the condition first originated. 

While the boy was being thrown onto the ground by the demon, the Lord spoke to the demon: “But Jesus rebuked the evil spirit, healed the boy and gave him back to his father” (Luke 9:42). With all of the crowd looking on, what did they see? The boy was delivered of the evil spirit and healed. What then took place in front of their eyes? The boy’s scars, burns, and cuts were healed instantly while they all looked on. No wonder Luke records that, “They were all amazed at the greatness of God” (v. 43). I would have loved to have seen their faces and the amazement that they had. I hope there are re-runs in heaven!

Afterward, the disciples had big questions. Mark tells us Jesus' explanation as to why the nine could not deliver the boy:


28When He came into the house, His disciples began questioning Him privately, “Why could we not drive it out?” 29And He said to them, “This kind cannot come out by anything but prayer” (Mark 9:28-29).

The disciples had gone from depending on Christ to pray for the sick and cast out demons to prayer that was less and dependent on forms and systems. They lacked the power that only comes through a lifestyle of prayer. The King James Version adds additional words: and fasting to Mark's testimony (Mark 9:29). In most English translations this is sometimes reflected in a little number attached to the text with the words "and fasting” added to the bottom of the page. In some English translations of the Bible, a whole verse is taken out of Matthew's Gospel, i.e., [“But this kind does not go out except by prayer and fasting”] (Matthew 17:21).

The problem is that some Greek manuscripts have the word fasting and some do not. I think it should be in the text, for it is our flesh that does not like to fast, but fasting and prayer together are a powerful force in the kingdom of God. There are some situations one comes into where we don't have the time to spend in fasting, so it is likely that Jesus is talking about a lifestyle of prayer and fasting. If we incorporate regular times of fasting with the daily discipline of prayer and mulling over Scripture, we will have power from God for every situation in our daily lives. Fasting and prayer bring a greater anointing, i.e., a more significant presence of the Spirit of Christ to one's life. In our day, there is a great need for men and women filled with the Spirit and exercising power and the authority of Christ for the needs of the lost and those bound by demonic spirits. The further we go into sin and degradation as a society, the more demonic spirits will manifest. Men and women of faith who know who they are in Christ are a significant threat to demons.

Symptoms of Demonic Influence


In the passage above we see symptoms of demonization in the boy. It would be a mistake to believe that demons only operate in a person's life in this way. I thought it would be helpful to list various symptoms of demonization. One needs to take care of the following list, as many of the things mentioned could be manifestations of our unchecked sinful nature. This list was taken from the notes of a Spiritual Warfare seminar by John Wimber and came from an unpublished paper by Tom White. Demonic influence can show up in five areas of a person's life:


  1. Spirit
    1. Powers of mind, ESP, precognitive abilities, occultic dreams.
    2. Inner perception of a separate personality, name, voice, or a “friend” who serves as a guide.
    3. A sense of being "different" or "special." This may connect with an interest in reincarnation.
    4. Fearful, bizarre dreams and/or night experiences.


  1. Mind
    1. Confusion, cloudiness of thought.
    2. Separation of mind from the body—spacing out, memory lapses.
    3. Inability to concentrate on scripture.
    4. Blockage in hearing and participating in prayer.
    5. Uncontrolled images and thoughts, i.e., sexual fantasies, cursings, obscenities, violent thoughts.
    6. Persistent dreams related to bizarre sex, occult, fear.
    7. Persistent battle with doubt (usually regarding scriptural truth).


  1. Will
    1. Uncontrollable, compulsive behaviors, most commonly sexual sin, anger, hatred, fear.
    2. Different personalities, “voices,” other identities.
    3. Uncontrollable surges of rebellion against authority.
    4. Intense urges toward violence.


  1. Emotions
    1. Severe depression apart from an identifiable cause.
    2. Uncontrollable, sudden fears.
    3. Unusual and not typical emotional experiences, i.e., laughter, sadness, crying, anger, etc.
    4. Intense guilt, accusation, worthlessness.
    5. Hate, anger, bitterness (inability to conquer through confession.)
    6. Severe depression and/or drive towards suicide.


  1. Body
    1. The eyes: fear, anxiety, anger. Difficulty in getting eye contact.
    2. Unnatural nervousness: especially at the mention of Jesus’ name, reading scripture, or direct prayer.
    3. Headaches, dizziness, shifts in body temperature, difficulty breathing.
    4. Persistent bodily ailments that elude medical diagnosis.
    5. Hallucinatory or auditory interference.
    6. Extreme, medically undiagnosed fatigue.[1]


Again, we must be careful in reading such a list for some of these things can be attributed to our sinful nature, natural sicknesses and diseases, and also chemical dependencies. These symptoms can also result from a damaged emotional history. It is unfortunate though, that the medical establishment, for the most part, does not accept that humanity is made up of a body, soul and spirit, something that Scripture is very clear about (1 Thessalonians 5:23). Anything of a spiritual nature is not considered. When we close our eyes to what the author of life has to say about how He made us, it is easy to dismiss spiritual symptoms. Most medical doctors would say that Jesus got it wrong and that He was treating a person wrongly, that he should have diagnosed certain drugs to heal the man's son, which is how he would have been treated in most hospitals today.

What strikes you about the following verse: "O unbelieving generation," Jesus replied, "how long shall I stay with you? How long shall I put up with you? Bring the boy to me" (v. 19). Why would Jesus be frustrated and disappointed with the nine disciples?


Luke’s narrative had told us that the disciples had gone out by six pairs and healed the sick and cast out demons (Luke 9:1-2). Jesus had also trained and sent out 72 others to do the same thing (Luke 10:1, 9, 17). Now, just before He departs for Jerusalem, and with it His departure from this Earth, the disciples are incapable of casting out a demon in front of Him. Doesn't it seem as if Jesus got upset and frustrated at the disciples? In Luke’s account of the same deliverance, Jesus called the nine disciples, “unbelieving and perverse” [or distorted] (Luke 9:41). This is what the Fall has done to the human race, making us an unbelieving people, having a distorted view of God and His ability to use us in ministry toward those held in bondage to sin and evil in this world. A person’s frustration is often visual evidence showing the things about which a person cares. Jesus cared that the disciples were able to minister in the power of God and be able to deliver people from bondage. Each of us is to learn to exercise the ministry of Jesus on the earth in the name of Christ. The nine disciples took the time to pray for the boy, but they moved from trusting the power and authority of Christ to believe that it was faith in the process. The presence of Christ on us is the key, not the method or system on which we tend to lean.


What happened to the disciple’s faith? They had ministered in this way before, so why could they not cast out the spirit out of the boy? It is essential to Christ that His Church understands that we are a supernatural people invested with divine power and authority to do His work in the world.


We live in a day where the Church in the West relies more on the intellect than the power of God. But the time has far gone for business as usual. We cannot rest on what we can do in our strength to get the gospel out to a lost world. We need the whole church to preach the whole gospel to the whole world! Do you know that the population of the world only passed one billion in the year 1830? Then it took 130 years before it got to two billion people. The world population is now over seven billion people (2018) and growing at the rate of one billion every ten years. More than half the amount of people who have ever lived are now alive. Think about that! Only as we step out in the power of our God, exercising His authority, will the church ever get into multiplication mode where we see whole cities come to Christ? Is that not possible? If it was possible in the Book of Acts why would it not be possible today?


Jesus was frustrated at the disciples because He wanted them to work under the power of the Holy Spirit, and not rely only on their abilities. Human intelligence and soul energy was not going to change the world. The power of God was, and is, the need of the hour! God’s work needs God’s power. When they asked why they couldn’t cast out the spirit from the boy, He told them it was because of their lack of faith. But then he explained something interesting, which some translations take out from the original Greek. “But this kind does not go out except by prayer and fasting” (Matthew 17:21). Some Greek manuscripts do not include this passage, so the New International Version translators decided to put the passage down at the bottom of the page. The King James Version includes it. What the Lord is saying is that a life characterized by prayer and fasting will always be ready to handle situations that are resistant to a life marked by a lack of prayer.


I am thankful for this nugget of truth, for it explains that there are some situations we encounter, which can only be resolved by a higher level of the presence and power of God upon us, which can come about only through a life of regular prayer and fasting. One needs time to fast and pray. It is often not possible to ask a person to come back at a later time so that we could fast and pray. If only the nine had known beforehand that they would encounter a spirit that would resist their commands to come out of the boy, they would have prepared themselves for the encounter. Jesus is advocating a lifestyle of prayer and fasting so that we would always be ready for any situation. I don't believe the words, "this kind," refers only to a strong evil spirit, I think it relates to stubborn conditions that each of us goes through which a typical habit of prayer has not resolved. In these instances, there can be a spiritual stronghold that needs to be broken by times of prayer and fasting.

He replied, "Because you have so little faith. Truly I tell you, if you have faith as small as a mustard seed, you can say to this mountain, 'Move from here to there,' and it will move. Nothing will be impossible for you" (Matthew 17:20).


I like to think of fasting as the Atom Bomb of the Holy Spirit. A desperate situation resolved through drastic measures—fasting. Fasting adds intensity, earnestness, and authority to prayer. Jesus is saying that if they would live a life of prayer and fasting they would have the faith of God to move mountains. I don't believe that He was talking about literal mountains; He was using a figure of speech concerning situations that are immovable apart from God's Spirit moving them for us. When Zerubbabel was building the second temple after Israel's dispersion in Babylon, he had such difficulties in the building work that the prophet Zechariah was sent to him, saying:

6So he said to me, "This is the word of the LORD to Zerubbabel: 'Not by might nor by power, but by my Spirit,' says the LORD Almighty. 7"What are you, O mighty mountain? Before Zerubbabel you will become level ground. Then he will bring out the capstone to shouts of 'God bless it! God bless it!' " 8Then the word of the LORD came to me: 9"The hands of Zerubbabel have laid the foundation of this temple; his hands will also complete it. Then you will know that the LORD Almighty has sent me to you. (Zechariah 4:6-9).

The mountain of difficulties that Zerubbabel faced in rebuilding the temple would not be overcome by their intelligence, fleshly might, and not by any power of their own (v. 6). In the passage above Zerubbabel was told that God would step in to the situation by His Spirit, and the mountain of difficulties would become a level plain as he exercised faith in God. Sure, I do agree that God can move mountains, but I don’t see any occasion where God would expect any of us to speak to real mountains to move out of our way. But He certainly will use us to speak authoritatively to situations that are like immovable mountains and see them become a level plain by God's Spirit. A mountain speaks of something that will not move; a situation where you cannot go around it, you have to go through it. We need the power of God to move the mountain!


Is there a stubborn situation in your life or in the life of a close friend or relative that may require fasting and prayer? If you can, share the situation.


The early disciples of Christ in the aftermath of the Resurrection lived this kind of life and turned the world upside down by the power of God flowing through them (Acts 17:6). Let's look at two examples of the disciples turning the world upside down:


The Early Church Practiced Fasting


1In the church at Antioch there were prophets and teachers: Barnabas, Simeon called Niger, Lucius of Cyrene, Manaen (who had been brought up with Herod, the tetrarch) and Saul. 2While they were worshiping the Lord and fasting, the Holy Spirit said, "Set apart for me Barnabas and Saul for the work to which I have called them." 3So after they had fasted and prayed, they placed their hands on them and sent them off (Acts 13:1-3).


Acts 11:21 describe the church at Antioch as having a significant number of people that turned to the Lord. We see in the passage above that a leadership team of individuals was spending time with God, worshiping and fasting together. Since there were prophetic people among them, (v. 1) the Holy Spirit spoke through one of them to release Barnabas (Acts 4:36), and Saul, also named Paul the Apostle, into a unique ministry of church-planting. God spoke to them during a time of worshiping and fasting. They were sent out as a missionary team by the Body of Christ there in Antioch.


21They preached the good news in that city and won a large number of disciples. Then they returned to Lystra, Iconium, and Antioch, 22strengthening the disciples and encouraging them to remain true to the faith. "We must go through many hardships to enter the kingdom of God," they said. 23Paul and Barnabas appointed elders for them in each church and, with prayer and fasting, committed them to the Lord, in whom they had put their trust. (Acts 14:21-23).


After their first missionary journey, Barnabas and Paul later went back and sought the Lord’s blessing on the new leadership of the young churches by prayer and fasting for insight into who were the leaders that God wanted in the governmental position of elders. We cannot tell from the text if it was just Paul and Barnabas that were fasting or the whole church was engaged in the fast together.


In 2 Corinthians 11:27, Paul said, "I have labored and toiled and have often gone without sleep; I have known hunger and thirst and have often gone without food." The words "gone without food" should be translated that Paul had "often fasted." Just previously he wrote he involuntarily had known hunger and thirst, but Paul also voluntarily fasted from the food he had available. The King James Version translates the same passage: In weariness and painfulness, in watchings often, in hunger and thirst, in fastings often, in cold and nakedness (2 Corinthians 11:27).


If Paul was in a lifestyle of prayer and fasting often, and God used him so powerfully, we need to realize that this same power is available to us today. Perhaps the amount of prayer and fasting that Paul engaged in was the very thing that resulted in the great grace that was upon his life. Yes, God had a plan for Paul. The Lord answers when faith is expressed. Paul had a zealous faith and would not let God go. In one place he wrote:


9But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly about my weaknesses, so that Christ's power may rest on me. 10That is why, for Christ's sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong (2 Corinthians 12:9-10).


Paul's testimony was that he found a secret—the weakness of his strength brought the power of God upon him. He said he delighted in being weak so that Christ's power may rest upon him. One thing is sure; we need the power of God to be at work in the Church of the 21st century. It will take men and women who are dedicated to labor with God's energy at work in them and not the strength of our abilities apart from God's enablement. In another place, Paul writes:


To this end I labor, struggling with all his energy, which so powerfully works in me (Colossians 1:29).


It is Christ in us, the hope of glory that must do the works of the kingdom. When a man or woman seeks, through prayer and fasting, for God’s Spirit to have the reins of one’s life, then God can get the glory by doing His work through us. Heaven forbid that the Church should seek for the glory that is due only to Christ. That's why Paul could say to the church in Rome: “I know that when I come to you, I will come in the full measure of the blessing of Christ” (Romans 15:29). He had learned that the Spirit would work powerfully through him as he served the Lord through fasting and prayer. He fully expected that he would come with the Spirit's power.


How can fasting be worked into a busy schedule? What would you say to a person who said that they would be too weak to fast and pray?


Practical Advice about Fasting


  1. Don't start fasting for more than a day if you have never done it before. Building on success is wise. Start by fasting breakfast and lunch and plan to eat in the evening. Lengthen the amount of time as God leads you.
  2. If you usually drink tea or coffee, plan to kick the caffeine a day early so that the first day of a fast you are not dealing with a massive headache as well as no food in your stomach. I would encourage you to drink only water during fasting. Water helps in the cleansing of toxins from our bodies during fasting. There are one or two places where a person fasted having no water, but it is dangerous to go longer than three days without water. Moses was on a supernatural fast when he was with the Lord and fasting food and water. A person can die by going longer than three days without water.
  3. Keep a record of what you are experiencing and the kinds of prayers you are speaking. Later on, when you look back over your time of fasting, you will be much encouraged at the way God has answered prayer during your fast.
  4. If you are on medicine, check with your doctor and let him know what you are doing.
  5. Get hold of some books on fasting to encourage you. One of the best books I have read on fasting is God’s Chosen Fast by Arthur Wallis. I can also recommend Mahesh Chavda’s book, The Hidden Power of Prayer and Fasting, as well as Derek Prince’s book called, Shaping History Through Prayer and Fasting.
  6. Set aside normal meal times by going to your room and praying. Being around when food is cooking is challenging to overcome, especially in the first three days of a fast.
  7. Beware of the TV. One becomes aware of how many commercials on food there is on TV.
  8. In the first three or four days, the body burns up many of the toxins that are in our bodies due to the kinds of foods we consume in most western countries. You will feel weakness by the end of the first day until around the fourth day. This burning of the toxins is very healthy for you. During this time your urine becomes yellow, your breath smells horrible, and if it is winter, your body can get cold quickly. If you are on a fast of over four days, your strength will return once the toxins are burnt up. Fasting becomes easier at that point.
  9. You will experience greater clarity of mind during fasting. Read the Scriptures often and draw near to God in the midst of your fast.
  10. Fasting is not damaging to your health—fasting is normal to the animal kingdom. The hunger pangs that one starts to experience toward the end of the first day is just the body’s way of telling you that it is time for food. The cravings will die down.
  11. Read chapter 58 of the Book of Isaiah, the section on fasting, and be watchful over your motives.
  12. Fasting breaks bondages of sin and loosens the hold of bad habits and their rulership over your life.
  13. Pray for God to release the gifts of the Spirit in your life. Fasting opens one's life to new spiritual gifts from God because our spirit is humbled and sensitive to the Spirit of God's leading.
  14. Fasting helps in the loss of weight. Be careful that you don't overeat when you return to eating. During the fast, your stomach will shrink, and overeating after a fast could be dangerous. Anytime longer than a six-day fast should be broken with broth or easily digested food.
  15. There are different kinds of fasts. Daniel and his three friends went on a vegetable and water fast (Daniel 1:12). Later on, he fasted for three weeks on no choice food, meat or wine touched his lips (Daniel 10:2-3). Decide for yourself how you are going to fast. Ask God to show you what kind of fast you are to undertake.
  16. Try to avoid heavy exercising or taking long walks. It is easy to get so tired and want to break your fast early.
  17. An average healthy person can fast up to 40 days. Around that time, a person's hunger pangs will return, and at that point, a person starts to starve. Beyond 40 days our bodies begin to consume living cells rather than fat. Jesus fasted for forty days, and at that point, the Bible tells us that He was hungry. When the hunger pangs return, it is time to break your fast. Satan’s temptation of Jesus began at the forty-day mark when the hunger pangs started, tempting Him with bread (Matthew 4:2-3). It seems more than likely that all three temptations came on one day, the last day of His fast.


My Personal Experience of Fasting


Several years ago, my wife and I felt an urgent need to fast and pray for a person close to us. The person was struggling with some difficulties she was going through. We fasted on water alone. This was an attack of the enemy to separate her from her newfound faith in Christ. After ten days of prayer and fasting for this individual, she arrived at our door in tearful brokenness. We prayed and talked. Before this knock on the door by her, we had not made contact with her or asked her to come over; the Holy Spirit prompted her to come to our home. It was an answer to prayer. Although this individual still had some difficult years ahead, she returned to her faith in Christ and now has her own stories of answered prayer. Fasting will help to loosen bonds that the enemy has on a person's life, enabling them to respond freely to the promptings of the Holy Spirit. Maybe you have a loved one you have been praying for, and you desperately want to see a breakthrough. Is God asking you to fast and pray for them? Some situations will not change until one prays with prayer and fasting. Fasting, along with fervent prayer, is a powerful combination.


If you would like to study more on fasting, there is another study I wrote for the series Growing Faith, the study is number 9 and called: Fasting, Gods Secret Weapon

Homework: After prayer and dedication of your lives and home, go throughout your home asking the Spirit of God to show you any books, music, or anything that displease Christ in your home. Destroy it and ask the Spirit to bless your home with His peace.

Keith Thomas



[1] John Wimber, Spiritual Warfare, Demonization, Published by Mercy Publishing, 1988

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