'The sting of death is sin, and the power of sin is the law.'
He visualises death as like a vicious insect or scorpion with its poisonous sting. And what was death's sting? It was sin. Once man had sinned, he was sentenced to death. And subsequently all men sinned, and therefore all died. All were stung by sin. And it continues so to be. But then One came Who had not sinned, and yet He too was sentenced to death. He too died. And in that was Satan's error. For He Who died bore the sin of all who would be His (1 Corinthians 15:3), of all who had been given to Him by the Father (John 6:39). And thus was death rendered powerless. In Christ the power of sin was broken, the guilt of sin was removed, and for those who submitted themselves to Christ, death had no further sting. It was sheathed in Jesus Christ in Whom it could have no everlasting effect, because He was the ultimate sacrifice and the Lord of life.
‘And the power of sin is the Law.' Here too there is tragedy. The Law that should have given life gives only death, for it is the Law that condemns man unceasingly. When a man sins the Law points at him unerringly. It declares, ‘man, you have sinned, for you have broken one of my precepts.' And he knows then that he is doomed, and that death is the inevitable consequence. That he has no hope. He has sinned and he must die. And the more he sins the more the Law condemns him. The Law which should have been his hope, and should have meant that he could live triumphantly, could now only condemn. By his sin man has turned God's blessing into a curse. For once he had sinned it became his accuser.
This idea of the Law is amplified later in Romans 7:7-14. But whether Paul here means the Law of Moses, or the general law that governs mankind (Romans 2:15) we cannot be certain. There has been no prior emphasis on the Law in 1 Corinthians. Yet the question is not a vital one. To Paul God's Law underlay all law (Romans 2:14). And the principle remains the same. Moral law, which is intended for good, condemns once sin is committed.