Mark 9:23

If Thou canst Believe - This was an answer to the inquiry above. I can furnish a sufficiency of power, if thou canst but bring faith to receive it. Why are not our souls completely healed? Why is not every demon cast out? Why are not pride, self-will, love of the world, lust, anger, peevishness, with all the other bad tempers and dispositions which constitute the mind of Satan, entirely destroyed? Alas! it is because we do not believe; Jesus is able; more, Jesus is willing; but we are not willing to give up our idols; we give not credence to his word; therefore hath sin a being in us, and dominion over us.

If thou canst believe - This was an answer to the request, and there was a reference in the answer to the "doubt" in the man's mind about the power of Jesus. "I" can help him. If thou" canst believe," it shall be done. Jesus here demanded "faith" or confidence in his power of healing. His design here is to show the man that the difficulty in the case was not in the want of "power" on his part, but in the want of "faith" in the man; in other words, to rebuke him for having "doubted" at all whether he "could" heal him. So he demands faith of every sinner that comes to him, and none that come without "confidence" in him can obtain the blessing.

All things are possible to him that believeth - All things can be effected or accomplished - to wit, by God - in favor of him that believes, and if thou canst believe, this will be done. God will do nothing in our favor without faith. It is right that we should have confidence in him; and if we "have" confidence, it is easy for him to help us, and he willingly does it. In our weakness, then, we should go to God our Saviour; and though we have no strength, yet "he" can aid us, and he will make all things easy for us.

9:23 If thou canst believe - As if he had said, The thing does not turn on my power, but on thy faith. I can do all things: canst thou believe?