21 And Jesus questioning the father said, How long has he been like this? And he said, From a child. 22 And frequently it has sent him into the fire and into the water, for his destruction; but if you are able to do anything, have pity on us, and give us help. 23 And Jesus said to him, If you are able! All things are possible to him who has faith. 24 Straight away the father of the child gave a cry, saying, I have faith; make my feeble faith stronger. 25 And when Jesus saw that the people came running together, he gave orders to the unclean spirit, saying to him, You, spirit, who are the cause of his loss of voice and hearing, I say to you, come out of him, and never again go into him. 26 And after crying out and shaking him violently, it came out: and the child became like one dead; so that most of them said, He is dead. 27 But Jesus took him by the hand, lifting him up; and he got up.
Matthew Henry's Commentary on Mark 9:21-27
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.