Adam Clarke on 1 Corinthians 15:56

The sting of death is sin - The apostle explains himself particularly here: death could not have entered into the world if sin had not entered first; it was sin that not only introduced death, but has armed him with all his destroying force; the goad or dagger of death is sin; by this both body and soul are slain.

The strength of sin is the law - The law of God forbids all transgression, and sentences those who commit it to temporal and eternal death. Sin has its controlling and binding power from the law. The law curses the transgressor, and provides no help for him; and if nothing else intervene, he must, through it, continue ever under the empire of death.