John Calvin Commentary Mark 10:52

"And Jesus said unto him, Go thy way; thy faith hath made thee whole. And straightway he received his sight, and followed him in the way." — Mark 10:52 (ASV)

Your faith has saved you. By the word faith is meant not only a confident hope of recovering sight, but a loftier conviction, which was that this blind man had acknowledged Jesus to be the Messiah whom God had promised. Nor must we imagine that it was only some confused knowledge, for we have already seen that this confession was taken from the Law and the Prophets.

For the blind man did not at random bestow on Christ the name Son of David, but embraced Him as that person whose coming he had been taught by the divine predictions to expect. Now Christ attributes it to faith that the blind man received sight; for though the power and grace of God sometimes extend even to unbelievers, yet no one enjoys His benefits in a right and profitable manner unless he receives them by faith; indeed, the use of the gifts of God is so far from being advantageous to unbelievers that it is even hurtful.

And therefore, when Christ says, your faith has saved you, the word saved is not limited to an outward cure, but includes also the health and safety of the soul; as if Christ had said that by faith the blind man found God to be gracious to him and had his wish granted. And if it was in regard to faith that God bestowed His favor on the blind man, it follows that he was justified by faith.