Jerome
Catena Aurea · Matthäusevangelium 17
And when they were come to the multitude, there came to him a certain man, kneeling down to him, and saying, Lord, have mercy on my son: for he is lunatick, and sore vexed: for ofttimes he falleth into the fire, and oft into the water. And I brought him to thy disciples, and they could not cure him. Then Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I suffer you? bring him hither to me. And Jesus rebuked the devil; and he departed out of him: and the child was cured from that very hour.
In saying, And I brought him to thy disciples, and they could not heal him, he covertly accuses the Apostles, whereas that a cure is impossible is sometimes the effect not of want of power in those that undertake it, but of want of faith in those that are to be healed,