In this passage of scripture, Jesus had just come down off the mount of transfiguration. Most of his disciples were below and they were unsuccessfully trying to free a boy from demonic possession. Jesus exhorts them that anything is possible to him who believes. However, when the disciples ask Jesus specifically why they couldn’t cast this demon out, Jesus replies that “this kind” of devil only comes out by prayer and fasting (some versions just say “prayer”.)
All things are possible to the person who believes. Prayer and fasting is not just a discipline that somehow in its own right grants new power. It is not in the rote action, but in the transformational process. What Jesus reveals in this passage is that prayer and fasting can take us to a level of faith that is unobtainable otherwise. “Nothing but prayer and fasting”. If there is any stronghold, sickness or disease, any spiritual oppression that has persisted, there is a new level of faith, a new level of belief that can be gained in the secret place of prayer and fasting.
God’s power and love are able to conquer any mountain we face, but it is our challenge to believe in Him. The closer we get to Him, the more we understand the limitlessness of His power and His love for us. This increasing revelation spurs our belief to new levels. Levels which see results. May you speak to your mountain today, and may it cast itself into the sea today!