‘Till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.’ Here finally the death penalty threatened in Genesis 2:17 is brought into effect.
Why didn’t Adam and Eve die immediately, for God had said, ‘in the day that thou eatest thereof thou shalt surely die’, and yet Adam lived 930 years after he sinned? Although Adam did not die physically, yet he immediately died spiritually. Scripture describes the unconverted man is spiritually dead even while he is physically alive (Ephesians 2:1). Those who believe have reversed this part of the curse and passed from a state of death to a state of life (John 5:24). Adam died spiritually the moment he sinned. This death meant that he no longer had fellowship with God, that he stood condemned by God’s commandments, that he no longer knew God because his mind was darkened. And from that time onwards it was also inevitable that he would die physically, and through the ageing process he saw that death was coming in slow motion. Again, this was part of the mercy of God for his life was not terminated at once, but he had time to see what was coming, time in which he could repent of his sin and turned to God for salvation.
Was Adam already mortal before the fall, and was the threat ‘Thou shalt surely die’ only intended in the spiritual sense? Calvin answers this by quoting 1 Corinthians 15:22 to show that death came because of sin. He insists that ‘Truly, the first man would have passed to a better life, had he remained upright; but there would have been no separation of the soul from the body, no corruption, no kind of destruction, and, in short, no violent change.’