He answereth him, and saith, O faithless generation, how long shall I be with you? how long shall I suffer you? bring him unto me.

Jamieson-Fausset-Brown Bible Commentary

19. He answereth him, and saith, O faithless generation-"and perverse," or "perverted" (Mt 17:17; Lu 9:41).

how long shall I be with you? how long shall I suffer you?-language implying that it was a shame to them to want the faith necessary to perform this cure, and that it needed some patience to put up with them. It is to us surprising that some interpreters, as Chrysostom and Calvin, should represent this rebuke as addressed, not to the disciples at all, but to the scribes who disputed with them. Nor does it much, if at all, mend the matter to view it as addressed to both, as most expositors seem to do. With Bengel, De Wette, and Meyer, we regard it as addressed directly to the nine apostles who were unable to expel this evil spirit. And though, in ascribing this inability to their "want of faith" and the "perverted turn of mind" which they had drunk in with their early training, the rebuke would undoubtedly apply, with vastly greater force, to those who twitted the poor disciples with their inability, it would be to change the whole nature of the rebuke to suppose it addressed to those who had no faith at all, and were wholly perverted. It was because faith sufficient for curing this youth was to be expected of the disciples, and because they should by that time have got rid of the perversity in which they had been reared, that Jesus exposes them thus before the rest. And who does not see that this was fitted, more than anything else, to impress upon the by-standers the severe loftiness of the training He was giving to the Twelve, and the unsophisticated footing He was on with them?

Bring him unto me-The order to bring the patient to Him was instantly obeyed; when, lo! as if conscious of the presence of his Divine Tormentor, and expecting to be made to quit, the foul spirit rages and is furious, determined to die hard, doing all the mischief he can to this poor child while yet within his grasp.

Matthew Henry's Concise Commentary

9:14-29 The father of the suffering youth reflected on the want of power in the disciples; but Christ will have him reckon the disappointment to the want of faith. Very much is promised to our believing. If thou canst believe, it is possible that thy hard heart may be softened, thy spiritual diseases may be cured; and, weak as thou art, thou mayest be able to hold out to the end. Those that complain of unbelief, must look up to Christ for grace to help them against it, and his grace will be sufficient for them. Whom Christ cures, he cures effectually. But Satan is unwilling to be driven from those that have been long his slaves, and, when he cannot deceive or destroy the sinner, he will cause him all the terror that he can. The disciples must not think to do their work always with the same ease; some services call for more than ordinary pains.