Calvin's Commentaries, Vol. 32: Matthew, Mark and Luke, Part II, tr. by John King, [1847-50], at sacred-texts.com
22. And he cometh to Bethsaida, and they bring to him a blind man, and implore him to touch him. 23. Then taking the blind man by the hand, he led him out of the village. And when he had spat on his eyes, and laid his hands upon him, he asked him if he saw any thing. 24. And he looking up said, I see men; for I perceive them walking as if they were trees. 25. Then he again laid his hands upon his eyes, and desired him to look; and he was restored, so that he saw them all clearly. 26. And he sent him away to his own house, saying, Neither enter into the village, nor tell it to any one in the village.
This miracle, which is omitted by the other two Evangelists, appears to have been related by Mark chiefly on account of this circumstance, that Christ restored sight to the blind man, not in an instant, as he was generally accustomed to do, but in a gradual manner. He did so most probably for the purpose of proving, in the case of this man, that he had full liberty as to his method of proceeding, and was not restricted to a fixed rule, so as not to resort to a variety of methods in exercising his power. On this account, he does not all at once enlighten the eyes of the blind man, and fit them for performing their office, but communicates to them at first a dark and confused perception, and afterwards, by laying on his hands a second time, enables them to see perfectly. And so the grace of Christ, which had formerly been poured out suddenly on others, flowed by drops, as it were, on this man.
Mark 8:24. I see men. Our Lord had put the question to the blind man for the sake of his disciples, to inform them that the man had received something, but that hitherto nothing more than a slight commencement of the cure had been effected. The reply is, that he sees men, because he perceives some persons walking who are upright like trees By these words he acknowledges that his sight is not yet so clear as to distinguish men from trees, but that he has already obtained some power of seeing, because he conjectures from the motion that those whom he perceives to be in an erect posture are men; and it is in this respect that he says they are like trees We see then that he speaks only by conjecture when he says that he sees men
26. And he sent him away to his house. Christ does not suffer him to return to Bethsaida, where there were many that had beheld the miracle. This is conjectured by some to have been done, because Christ intended to punish the inhabitants of that place by depriving them of the enjoyment of his favor. Whatever might be the reason, it is certain that no miracle was performed by him in order to remain perpetually buried, but that he intended to have it concealed along with many others, till, after having expiated by his death the sins of the world, 435 he should ascend to the glory of the Father.
“Iusques a ce qu’ayant par sa mort accompli la satisfaction des pechez du monde;” — “till having by his death rendered full satisfaction for the sins of the world.”