Jesus, as the son of man, became sin in the sense He assumed our ruined and condemned humanity indwelt by our selfishness and self-love, but Jesus as the son of man said no to sin every day of His life. Hence He was perfect in obedience. This satisfied the positive demands of God's law. But because He took us, in our fallen condition, that life had to died. Here Christ suffered the justice of the law, not for sinning, but because He assumed our humanity unfit for heaven. That old life died forever. In the resurrection Christ was raised with our fallen humanity. He was raised in a glorified, perfect humanity free from indwelling sin.