The Lord God had added this sanction to his covenant with Adam: “In the day that thou eatest thereof thou shalt surely die” (Gen. 2:17). The exegesis of Genesis 3 supports the interpretation of this death as a threefold penalty.
First, the immediate effect of Adam’s sin was spiritual death. Man’s rebellion against God’s word ruptured his relationship with God, tearing open an immense chasm of hatred against God that expressed itself in shame, guilt, fear, and an unwillingness to accept personal responsibility (Gen. 3:7–13). The depth of human depravity after the fall is shocking; it was a total lapse from spiritual life to spiritual death. This death was separation and alienation from life-giving fellowship with God (Eph. 2:1–3; 4:18). It involved the destruction of the core content of God’s image in man: spiritual knowledge, righteousness, and holiness (v. 24).
Adam’s immediate descendants manifested their spiritual state by worshiping in a way that was displeasing to God, by murdering, by committing sexual sin, and by refusing to repent but rather glorying in sin (Genesis 4). Genesis summarizes the human condition apart from God’s saving grace with these words: “The Lord saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually” (6:5). Once “very good” (1:31), man’s heart was now completely corrupted. The loss of God’s moral image did not leave a vacuum, but inward perversity. This condition was so pervasive that God killed every human being on earth by the flood, with the sole exception of Noah and his family. It remains pervasive today (Rom. 3:10–18).
Second, God sentenced man to physical death. Mankind’s mortality would soon show itself in bodily weariness and pain (Gen. 3:16, 19). In due time, it would claim each man’s life, and he would die (5:5, 8, 11; etc.). The spirit departs and the body, once so full of life and beauty, decays horribly into earth (3:19). “Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it” (Eccles. 12:7). God’s image bearer on earth was subjected to futility. Mortality seized mankind in the garden and began to execute God’s sentence of death on every human being at the time of God’s choosing (Job 14:5, 14; Heb. 9:27).
Third, man became subject to eternal death—the ultimate manifestation of death. Though the full doctrine of hell is not revealed in the account of the fall, we do find it foreshadowed there. God banished man from the earthly paradise where eternal life was promised and available, then armed his holy angels against man (Gen. 3:24). Earth rose up against man to frustrate his labors and finally take his life (vv. 17–18). Where shall man go, if both heaven and earth reject him? He must go to an accursed place of divine wrath.
Sin incurs God’s curse (Gen. 3:14; Gal. 3:10). This curse has not yet come in all its fullness, for God continues to grant humanity many blessings in this world. He did not pronounce the first man and woman “cursed” like the Devil. However, God’s curse does fall upon unrepentant sinners (Gen. 4:11; 9:25; 12:3), for they are the spiritual offspring of the Devil (1 John 3:10–12). That curse will manifest itself fully in the last day, when Christ will say to the wicked, “Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels” (Matt. 25:41). The very thought of hell should make us tremble. Yet this is the culmination of the death that Adam brought upon the human race.1
Beeke, Joel R., and Paul M. Smalley. 2020. Reformed Systematic Theology: Man and Christ. Vol. 2. Wheaton, IL: Crossway.