What does "you shall surely die" mean in Genesis 2:17?

Nor can spiritual death, or "death in trespasses and sins," be possibly what God speaks of in His threatening to Adam. This is indeed the spiritual state which is the result of the fall but the moral state of a criminal is a very different thing from the judgment upon the criminal. Man's depravity is what he is condemned for, not what he is sentenced to; and these things cannot be synonymous. "Dust thou art, and unto dust shalt thou return" is thus the only possible, as it is the divinely given, interpretation of the announcement, "In the day thou eatest thereof thou shalt surely die."

"Thou shalt surely die" means literally "dying thou shalt die." This does not mean "eternal death," but "physical death."

Then came the prohibition, not to eat of the tree of the knowledge of good and evil. In the day that Adam should eat of it he would surely die. Not that he should die the very day he partook of the fruit of the tree, but that the process of death would then begin in his body, and death would inevitably ensue.

Moreover, he was warned as to the consequence of disobedience. If he acquired the knowledge of good and evil by disobedience, he would be unable to perform the good because enslaved by the evil. This would bring him under the power of death immediately. As we discover in the next chapter, he would not at once suffer the death of the body, which involves the dissolution of existing personality by separating the spiritual part from the material part of man. But he would at once suffer complete severance spiritually and morally from God, his Creator, which is death in its more intense form. In that sense he would die the very day in which he ate of the forbidden tree. To obey the one prohibition was his responsibility.

In the day that he sinned Adam died in the primary sense, that is, an infinite gulf yawned between him and God as the account shows. He became, in New Testament language, "dead in trespasses and sins" (Eph. 2:1).

1.—Does death, in Ezekiel 18:20 , where the words are, “The soul that sinneth, it shall die,” mean extinction?—No; neither there nor anywhere else, where it is used in Scripture. Annihilationists say that the judgment of sin is the death of the soul. But Scripture never so speaks. Nor does it speak of the death of the body. It is the man who dies, not his body or his soul. The word in Ezekiel 18:20 , is the person—the individual—not the father for the son, but the person who sins, he shall die. The word “soul” is so used in 1 Peter 3:20; 4:19. 2.—What do the words, “shall not see life,” in John 3:36 , mean?—If he never sees life, must he not be exterminated? Existence and life are not synonymous. All have the former—saint and sinner alike; only the former have “life,” as the word is here and elsewhere used. (See John 17:3; Rom. 6:23) Eternal life is the possession of the believer now, and in the future. The unbeliever “hath not life” (1 John 5:12 ) now; and of him it is said that he “shall not see life” hereafter. Yet he exists without it, as we know. That he shall continue to exist while never seeing it, is equally sure, as the closing words of the verse, “The wrath of God abides on him,” solemnly tell. Wrath cannot “abide” upon a nonentity. Endless existence is common to all men and angels; eternal life is the present possession of believers only (John 5:24 ). Immortality, which applies to a condition of life in the future, they look for (Rom. 2:7), and will “put on”, (1 Cor. 15:53 ) at the coming of the Lord. 3—How was the word spoken to Adam, in Genesis 2:17, “Thou shalt surely die,” fulfilled? — Not by natural death, for he lived 930 years. Nor was it “extinction of his being,” as Annihilationists say, for neither “in the day” Adam ate of the tree did his being become extinct, nor is it now. Nor did the promise of redemption suspend or postpone the sentence. When Adam sinned, the threatened death came upon him that day. His near relationship to God was broken. He was severed from His presence by sin; such is death in its deepest sense (see Eph. 2:1; 4:18 ). Yet he existed, as sinners still exist “without God”; so Rom. 5:12-13, clearly tells us. And if, while now without life in Christ, fallen angels and sinful men exist, so, in the disembodied and the eternal states; they shall exist, as Scripture fully shows (see 2 Pet. 2:4; Rev. 20:10; Luke 16:23 ; Rev. 20:15).

As the acorn contains in itself the germ of what will in due time develop into the oak tree, so the few but pregnant words of Genesis 3:15 contain the announcement of God's future purposes of grace overcoming the power of evil. God had said unto Adam, "Of the tree of the knowledge of good and evil thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die." No doubt the instant Adam disobeyed he became mortal, i.e. liable to death, through physical necessity, and at the same moment he fell into a state of spiritual death, i.e. the severance of the soul from God, alienation from Him, and enmity to Him in consequence of a nature now insubject to Him. In no sense does death to a human being mean annihilation; — even though the body returns to the dust, out of which Adam was originally and immediately created, it will be raised again. The breath which God breathed into Adam's nostrils endowed him with a rational and imperishable soul. Nevertheless life and incorruption, as well as the second death and eternal judgment, were brought to light by the gospel, and the expressions in the Old Testament, "Thou shalt surely die," and "the soul that sinneth it shall die," seem to speak solely of the death of the body, and with reference to God's government in this world.

Our first parents took of the tree of the knowledge of good and evil, and thus disobeyed God’s prohibition. The penalty was death—“in the day that thou eatest thereof thou shalt surely die” (Gen. 2:17). The marginal reading is “HEB. dying thou shalt die,” that is to say, the process of death began the moment sin was committed, just as if you plucked a flower in your garden, that moment it begins to die. You may put it in water and retard the process, but it is true of that flower “dying it shall die”—surely and slowly, death ensues.

At the beginning we get the strongest expression of the holiness and righteousness of God — "In the day that thou eatest thereof thou shalt surely die." Here the Lord attaches to the first commission of evil nothing less than complete separation from Himself; for He is the living God. As such He had just shown Himself; He had just become the source of all that in that moment was surrounding Him in earth, air, and seas; He was the living and life-giving God, and, therefore, a state of death was a state of separation from Him. And this state is announced to be the sure and immediate doom of the creature on the moment of his commission of evil. What a strong assertion, thus, at the very outset, of the purity of God, of the great truth that "God is light, and in Him is no darkness at all;" the creature that becomes a child of evil, a child of darkness, must at once be an exile from Him — "In the day that thou eatest thereof thou shalt surely die."

The penalty of eating of the tree of knowledge was, for Adam, death — physical death; but this necessarily the sign of the judgment of God, of separation between himself and God, of which the other is the image. For if death is the separation between soul and body, the separation of God from the soul is death also.