Satan's heresy that "You shall not surely die," when expanded, claims that we are already immortal, so death has no real hold over us. This idea, proposed at the very beginning, has thrived throughout history. Mainstream Christianity calls it the doctrine of the immortality of the soul, while various Eastern religions contain it in beliefs such as reincarnation. Whatever its moniker, the belief that human beings possess a spiritual, eternally conscious, imperishable component is a major tenet of nearly every religion throughout man's history. In our modern culture, books and movies abound with examples of the spirits of the dead hovering around the living characters, giving them comfort, aid, and encouragement. It is taken as given that death is not the end; somehow, one's conscious spirit will live on when the physical body perishes.
The Gnostic belief in the dualism of flesh and spirit—with the flesh being evil and something to be freed from, while the eternal spirit was good—also originated in the lie Satan told Eve. Gnostics, in general, believed that the purpose of human existence was to return to the spiritual realm from whence all originated. Death, then, was seen as liberation of the spirit.
First, consider how this belief affects a person's attitude and way of life. When Satan undermined the death penalty for disobedience, in addition to sowing further distrust in what God says, he also blunted one of the keenest elements of human motivation, continued self-preservation. If life beyond the grave is assured, how this life is lived makes little difference. It is like guaranteeing a college freshman that he will receive a doctorate degree, regardless of whether anything is learned, any work is done, any classes are attended, or any tuition is paid. While the student may indeed expend some effort, the motivation to apply himself wholeheartedly to his education will be substantially weakened. It would be so easy to slack off and postpone catching up to some time next week. After all, if the goal is certain, why worry about the details in the meantime?
Spiritually, the result is the same. If one already has immortality, and is eternally saved, there is no pressing reason to resist the pulls of carnality. Resisting Satan matters little. Devoting one's life to growing and overcoming has no urgency. Sin is no big deal. Why should one study to come to know God and His truth? Believing that one already possesses eternal life removes the urgency to live according to the desires and requirements of the Creator. At best, all that remains is the vague guidance of "just be a good person."
The Bible teaches that there can be life after death through the resurrection from the dead. Eternal life is ours only if God supplies it, and not because we possess an immortal soul:
» God tells us, "Behold, all souls are Mine; the soul of the father as well as the soul of the son is Mine; the soul who sins shall die." (Ezekiel 18:4; emphasis ours throughout). God repeats this in Ezekiel 18:20. Clearly, it is possible for a "soul" to die.
» Paul instructs in Romans 6:23 that "the wages of sin is death," not eternal life—not even eternal life in ever-burning hell. As with Ezekiel 18, sin incurs the death penalty. Satan, though, would have us believe that since death is not a real threat, sin is no big deal. It is only because of God's grace that we are not struck down immediately—not because of any inherent immortality within us—as the rest of Romans 6:23 explains: "but the gift of God is eternal life in Christ Jesus our Lord." Eternal life is a gift, not an inborn quality.
» I Timothy 6:16 says that God "alone has immortality"—not any member of the human race, Christians included!
» Romans 2:7 promises "eternal life to those who by patient continuance in doing good seek for glory, honor, and immortality," again proving that eternal life is a gift, not a right, and that immortality must be sought (by "doing good") rather than assumed to have it already.
» Finally, in the "Resurrection Chapter," I Corinthians 15, Paul explains when Christians receive immortality:
Now this I say, brethren, that flesh and blood cannot inherit the Kingdom of God; nor does corruption inherit incorruption. Behold, I tell you a mystery: We shall not all sleep, but we shall all be changed—in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised incorruptible, and we shall be changed. For this corruptible must put on incorruption, and this mortal must put on immortality. So when this corruptible has put on incorruption, and this mortal has put on immortality, then shall be brought to pass the saying that is written: "Death is swallowed up in victory." (I Corinthians 15:50-54)
It is not until "the last trumpet," when Jesus Christ returns, that the dead will be resurrected and given immortality (I Thessalonians 4:16). At this time, the saints will be changed and given new spiritual bodies (I Corinthians 15:49; I John 3:2). Clearly, immortality is not given until the resurrection from the dead, which does not take place until Jesus Christ returns.
That God must resurrect a person for him to continue living means that He retains sovereignty. He is not obliged to grant eternal life to anyone who demonstrates, once he has the opportunity to know God, that he is not willing to be subject to His way of life. However, by belittling the truth about the resurrection from the dead, and telling people that they already have immortality, Satan can distract them from a basic reason why they need to listen to God—so that they may be resurrected and continue living!
David C. Grabbe
Whatever Happened to Gnosticism? Part Three: Satan's Three Heresies