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.

20. And they brought him unto him: and when he saw him, straightway the spirit tare him—Just as the man with the legion of demons, "when he saw Jesus, ran and worshipped Him" (Mr 5:6), so this demon, when he saw Him, immediately "tare him." The feeling of terror and rage was the same in both cases.

and he fell on the ground, and wallowed foaming—Still Jesus does nothing, but keeps conversing with the father about the case—partly to have its desperate features told out by him who knew them best, in the hearing of the spectators; partly to let its virulence have time to show itself; and partly to deepen the exercise of the father's soul, to draw out his faith, and thus to prepare both him and the by-standers for what He was to do.