Drive Out Unbelief

“He said to them, “Because of your little faith. For truly, I say to you, if you have faith like a grain of mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move, and nothing will be impossible for you. [21]But this kind never comes out except by prayer and fasting” (Matthew 17:20-21, ESV).


Several versions of the Bible do not include verse 21 in Matthew 17. In an attempt to study the reason, I have discovered that not only could a long explanation be written on the subject, but that understanding Greek would be beneficial. One thing I know is true about Matthew 17:21 is that it is a verse that jumps off the page at me, and explains how I can overcome unbelief. Jesus was saying in this verse that fasting and prayer are ways of driving it out of my life.

.In this chapter Jesus has just come down off the mountain where he has been with Peter, James, and John. These three disciples have witnessed the incredible sight of Jesus speaking with Elijah and Moses. Now Jesus is suddenly approached by a man whose son has been tormented by a demon since he was a child. The other disciples have been unable to help this man’s son, and have just asked Jesus why they were unable to rid the son of his demon. Jesus answers that it is because of their little faith. In that illusive verse 21, Jesus explains that faith—strong enough to cast out the son’s demon—is discovered through prayer and fasting. Prayer and fasting are tools God gives us to help us overcome the natural unbelief that comes through our human desire to understand the “why and how” of everything. The name of Jesus can move mountains and drive out demons. His power is greater than our need to control and analyze. Faith to believe that He can move mountains can be found through the disciplines of prayer and fasting.

Unbelief is a “personal demon” that keeps you from believing in the faithfulness of God. Do you suffer from fear and a lack of trust in God? Are you tormented by feelings of failure and inadequacy? Do you drive yourself crazy by analyzing the reason behind everything? Whatever your unbelief, it can be conquered. As verse 21 reveals, prayer and fasting are two disciplines that make a difference.

Prayer isn’t just telling God what you desire, but is about listening and understanding what He desires. Prayer doesn’t change God; it changes you. When you enter into holy communication with God, the Spirit of the Lord within you prays to the Holy Spirit. “The Holy Spirit helps us in our weakness. For example, we don’t know what God wants us to pray for. But the Holy Spirit prays for us with groanings that cannot be expressed in words” (Romans 8:26, NLT). When you get to this depth in prayer, you have surrendered control and your need to analyze and understand with the human mind. When you release your heart and mind to the Holy Spirit praying for you, you are able to receive faith without the analytical perspective the mind always attempts to interject. The shield of faith grows stronger in your life.


Fasting focuses the mind on God instead of what you want or desire. It brings you to a place of peace where your mind has surrendered your need to His need. “You will keep in perfect peace him, whose mind is steadfast, because he trusts in you” (Isaiah 26:3). You can experience supernatural peace when the mind surrenders its struggle for control. (Philippians 4:6-7). When the human mind is bypassed, the need for reassurance is gone. Jesus spoke of this spiritual plane when he said to Satan in the desert, "Man doesn’t live on bread alone, but on every word that comes from the mouth of God" (Matthew 4:4). In another instance, the disciples insisted that Jesus eat, and he said, “I have food to eat that you know nothing about”. The disciples didn’t see any food. “My food,” Jesus explained, “is to do the will of him who sent me to finish His purpose" (John 4:32-34). Fasting draws you away from physical need and brings you closer to God. It gives spiritual sustenance which produces greater faith.


When we surrender control to God—whether in prayer or by fasting—we receive more of the Lord’s strength to handle life’s uncertainty. As we grow in these disciplines, sensitivity to the Holy Spirit increases, revealing our own inadequacy, and teaching us how to walk by faith and not by sight (2 Corinthians 5:7). On the mountain, Peter, James, and John witnessed an amazing sight. It created emotional fervor in these three disciples, and then later, when they came down off the mountain, the other disciples were unable to cast out a demon. Jesus called them an unbelieving generation. Feelings on the mountain don’t inspire greater faith, but spiritual training through disciplines like prayer and fasting do! Jesus Christ reveals clearly by word and deed that He is all that is necessary to have great enough faith to cast out unbelief.


Greater faith is the only way to end unbelief's ability to control your life. Prayer and fasting are two disciplines which inspire greater faith. I don't want the things that I have allowed to define who I am to have the ability to always define me. I want a strong enough faith to believe God over my feelings. I am a new creature in Christ (2 Corinthians 5:7). And I want to be new in every way.