Within Judaism, forgiveness ultimately belonged to God, though priests and prophets could announce or mediate what God had granted. Jesus' pronouncement is striking because he speaks directly and personally to the man's guilt.
The scribes' accusation of blasphemy shows that they perceive a theological problem, not merely a breach of etiquette. Jesus responds by demonstrating rather than withdrawing his claim.
The Old Testament repeatedly presents the LORD as the one who blots out transgression and forgives iniquity. Isaiah 43:25 emphasizes God's own action in removing sins, while Psalm 103 praises the LORD who forgives all iniquity.
Daniel 7 supplies the broader background for the Son of Man as a figure receiving extraordinary authority from the Ancient of Days, a theme Matthew develops further later in the Gospel.
Jesus first addresses the man's deepest need: 'Your sins are forgiven.' When the scribes inwardly accuse him of blasphemy, Jesus exposes their thoughts and asks which is easier, the unseen declaration of forgiveness or the visible command to walk.
He then heals the paralytic expressly so that they may know that the Son of Man has authority on earth to forgive sins. The miracle functions as visible confirmation of the invisible claim.
The passage is one of the clearest Synoptic examples of Jesus exercising a prerogative closely associated with God. Jesus does not retreat to the claim that he merely announces forgiveness already granted elsewhere.
Matthew does note that the authority is possessed by the Son of Man, and verse 8 speaks of authority given to men. That language should be allowed to stand. Even so, within the Gospel's cumulative portrait, Jesus personally exercises divine authority over sin and validates it by his sovereign act.
The scribes accuse Jesus inwardly of blasphemy; after the healing, the crowds are afraid and glorify God.