Bede the Venerable — as excerpted in the Catena Aurea on Mark 1:40-45

“(ubi sup.) Another reason why He touched him, was to prove that He could not be defiled, who freed others from pollution. At the same time it is remarkable, that He healed in the way in which He had been begged to heal. If thou will, says the leper, thou canst make me clean. I will, He answered, behold, thou hast My will, be clean; now thou hast at once the effect of My compassion.”