NOTES for Mat 17:14-27
Did the disciples really not have faith even as small as a mustard seed, since they could not cast the demon out of the young man? But we have read that earlier they had succeeded in doing this: the Lord Himself gave them authority over unclean spirits.
Apparently, the strength of faith is not simply the degree of our confidence in one or another truth about God or the world. The Lord connects faith and prayer, that is, communion with God, into one whole. This means that the issue is not confidence, but nearness to God, inward unity with Him. It is no accident that the Lord mentions fasting: when fasting, a person draws life-giving strength not from food, but from communion with God, living by His life. Such unity is not given to us once and for all. Today we may be closer to God, tomorrow farther from Him, although this is not always determined by our subjective feelings. Therefore, what separates faith from unbelief is not doubt about God's existence, but inner closedness to Him: prayerlessness, a lack of striving toward Him.