Matt 17:19-21, 19 Then the disciples came to Jesus privately and said, “Why could we not cast it out?”, 20, “So Jesus said to them, “Because of your unbelief; … 21 However, this kind does not go out except by prayer and fasting
As earlier seen, Christ explicitly commissioned His disciples to do these kind of miracles in His power. Less than a year later, they failed where they had succeeded before. They forgot the secret of slipping away to be in prayer before attempting to perform miracles. Christ explanation for their failure was that their faith was deficient. It’s in prayers where faith, power, God’s will is empowered. 2Cor 4:7 “But we have this treasure in jars of clay, to show that the surpassing power belongs to God and not to us.”
Jesus’ pattern and order of doing ministry is seen in Luke 5:16, “So He Himself OFTEN withdrew into the wilderness and prayed”, and the effect, vs. “17… And the power of the Lord was present to heal them”. His teachings and miracles were a result of Him slipping away from the crowd. Such was our Lord’s unexampled meekness that He preferred the silent deserts while He prayed to the applause of the multitudes. “No learning can make up for the failure to pray. No earnestness, no diligence, no study, no gifts will supply its lack” (E.M. Bounds). He who plows in the closet can expect to reap from the pulpit.