In the midst of Eden grew the tree of life, whose fruit had the power of perpetuating life. Had Adam remained obedient to God, he would have continued to enjoy free access to this tree and would have lived forever. But when he sinned he was cut off from partaking of the tree of life, and he became subject to death. The divine sentence, “Dust thou art, and unto dust shalt thou return,” points to the utter extinction of life. DD 14.2
Immortality, promised to man on condition of obedience, had been forfeited by transgression. Adam could not transmit to his posterity that which he did not possess; and there could have been no hope for the fallen race had not God, by the sacrifice of His Son, brought immortality within their reach. While “death passed upon all men, for that all have sinned,” Christ “hath brought life and immortality to light through the gospel.” Romans 5:12; 2 Timothy 1:10. And only through Christ can immortality be obtained. Said Jesus: “He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life.” John 3:36. Every man may come into possession of this priceless blessing if he will comply with the conditions. All “who by patient continuance in well-doing seek for glory and honor and immortality,” will receive “eternal life.” Romans 2:7. DD 14.3
The only one who promised Adam life in disobedience was the great deceiver. And the declaration of the serpent to Eve in Eden—“Ye shall not surely die”—was the first sermon ever preached upon the immortality of the soul. Yet this declaration, resting solely upon the authority of Satan, is echoed from the pulpits of Christendom and is received by the majority of mankind as readily as it was received by our first parents. The divine sentence, “The soul that sinneth, it shall die” (Ezekiel 18:20), is made to mean: The soul that sinneth, it shall not die, but live eternally. We cannot but wonder at the strange infatuation which renders men so credulous concerning the words of Satan and so unbelieving in regard to the words of God. DD 14.4
Had man after his fall been allowed free access to the tree of life, he would have lived forever, and thus sin would have been immortalized. But cherubim and a flaming sword kept “the way of the tree of life” (Genesis 3:24), and not one of the family of Adam has been permitted to pass that barrier and partake of the life-giving fruit. Therefore there is not an immortal sinner. DD 15.1
But after the Fall, Satan bade his angels make a special effort to inculcate the belief in man's natural immortality; and having induced the people to receive this error, they were to lead them on to conclude that the sinner would live in eternal misery. Now the prince of darkness, working through his agents, represents God as a revengeful tyrant, declaring that He plunges into hell all those who do not please Him, and causes them ever to feel His wrath; and that while they suffer unutterable anguish and writhe in the eternal flames, their Creator looks down upon them with satisfaction. DD 15.2