Luke 5:21

And the Scribes and the Pharisees began to reason
To think and say within themselves, and it may be to one another, in a private manner:

saying, who is this which speaketh blasphemies?
what vain boaster, and blaspheming creature is this, who assumes that to himself, which is the prerogative of God?

Who can forgive sins but God alone?
against whom they are committed, whose law is transgressed, and his will disobeyed, and his justice injured and affronted. Certain it is, that none can forgive sins but God; not any of the angels in heaven, or men on earth; not holy good men, nor ministers of the Gospel; and if Christ had been a mere man, though ever so good a man, even a sinless one, or ever so great a prophet, he could not have forgiven sin; but he is truly and properly God, as his being a discerner of the thoughts of these men, and his healing the paralytic man in the manner he did, are sufficient proofs. The Scribes and Pharisees therefore, though they rightly ascribe forgiveness of sin to God alone, yet grievously sinned, in imputing blasphemy to Christ: they had wrong notions of Christ, concluding him to be but a mere man, against the light and evidence of his works and miracles; and also of his office as a Redeemer, who came to save his people from their sins; and seem to restrain the power of forgiving sin to God the Father, whereas the Son of God, being equal with him, had the same power, and that even on earth, to forgive sin; (See Gill on Mark 2:7).