Jesus said unto him, if thou canst believe
As the man put an "if" on the power of Christ, Christ puts an "if" on the faith of the man; and tacitly suggests, that power was not wanting in himself, but faith in him; and should that cure not be performed, it would not be owing to any inability in him, but to his own incredulity. The Arabic version renders it, "what is this thy: saying, if thou canst do any thing?" What dost thou mean by it? Thou oughtest not to doubt of my power; there is no reason for it, after so many miracles wrought; upbraiding the man with his unbelief; and the Ethiopic version renders it thus, "because thou sayest, if thou canst": wherefore to show that power was not wanting in him, provided he had but faith, it follows,
all things are possible to him that believeth;
that is, "to be done" to him, as the Syriac and Ethiopic versions supply: for all things are not possible to be done by the believer himself, but all things are possible to be done for him, by God, or Christ, or the Spirit of God: thus our Lord, as he elsewhere does, ascribes that to faith, which is done by a divine power.