William Burkitt on Matthew 9:4

Our Saviour here gives the Pharisees a twofold demonstration of his godhead: first, By letting them understand that he knew their thoughts; for to search the hearts, and to know the thoughts, of the children of men, is not in the power either of angels or men, but the prerogative of God only.

Secondly, By assuming to himself a power to forgive sins; the Son of man hath power to forgive sins. Our Saviour here, by forgiving sins in his own name, and his own authority, doth give the world an undeniable proof and convincing evidence of his godhead: for, Who can forgive sins, but God only?