20 And they brought him unto him: and when he saw him, straightway the spirit tare him grievously; and he fell on the ground, and wallowed foaming. 21 And he asked his father, How long time is it since this hath come unto him? And he said, From a child. 22 And oft-times it hath cast him both into the fire and into the waters, to destroy him: but if thou canst do anything, have compassion on us, and help us. 23 And Jesus said unto him, If thou canst! All things are possible to him that believeth. 24 Straightway the father of the child cried out, and said, I believe; help thou mine unbelief. 25 And when Jesus saw that a multitude came running together, he rebuked the unclean spirit, saying unto him, Thou dumb and deaf spirit, I command thee, come out of him, and enter no more into him.
Matthew Henry's Commentary on Mark 9:20-25
Commentary on Mark 9:14-29
(Read Mark 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.