Why is it necessary to repent from sin? Sin originated in the Garden of Eden. God had commanded Adam, "'From the tree of knowledge of good and evil you shall not eat, for in the day that you eat from it you will surely die'" (Ge 2:17). But Eve "took from its fruit and ate; and she gave also to her husband with her, and he ate" (3:6). However "it was not Adam who was deceived, but the woman being deceived, fell into transgression" (1Ti 2:14). Transgression is defined as lawlessness and it is against God's instruction because God asked, "'Have you eaten from the tree of which I commanded you not to eat?'" (Ge 3:11). Consequently the sin had to be dealt with. The serpent was "more crafty than any beast of the field which the Lord God had made" (:1) and deceived Eve (:1-5). God told him Eve's seed "'shall bruise you on the head, and you shall bruise him on the heel'" (:15). This person who was promised was the seed of Abraham "that is, Christ" (Gal 3:16) because "'in your seed all the nations of the earth shall be blessed'" (Ge 22:18). Christ came "to destroy the works of the devil" (1Jn 3:8). Christ died that "He might render powerless him who had the power of death, that is, the devil" (Heb 2:14). This was all necessary because Adam was "the one who sinned" (Ro 5:16) and "by a man came death" (1Co 15:21), but "in Christ all shall be made alive" (:22).
"In Adam all die" (1Co 15:22). Paul says "you were dead in your trespasses and sins" (Eph 2:1). "The Lord saw that the wickedness of man was great on the earth, and that every intent of the thoughts of his heart was only evil continually" (Ge 6:5). These are the works of the devil that Christ had to overcome. Humans are "by nature children of wrath" (Eph 2:3) because they live in a worldly way "according to the prince of the power of the air" (:2). We "lived in the lusts of our flesh" (:3) and a person who indulges in "the desires of the flesh and mind" (:3) "is dead even while she lives" (1Ti 5:6). When Paul became aware of sin through the Law he said "it killed me" (Ro 7:11). But there is a way to "save his soul from death" (Ja 5:20). "When we were dead in our transgressions, [God] made us alive together with Christ" (Eph 2:5). Jesus said, "'You have no life in yourselves'" (Jn 6:53) so we are saved "according to His mercy, by the washing of regeneration and renewing by the Holy Spirit" (Titus 3:5). "Do not be conformed to this world, but be transformed by the renewing of your mind" (Ro 12:2). "Repent and return, so that your sins may be wiped away" (Ac 3:19). God accomplishes this because he said, "'I will put My Spirit within you'" (Eze 36:27). John said that Jesus "'will baptize you with the Holy Spirit'" (Mt 3:11). "Therefore if anyone is in Christ, he is a new creature" (2Co 5:17). "'That which is born of the Spirit is spirit'" (Jn 3:6). We are "born again to a living hope" (1Pe 1:3) "through the living and enduring word of God" (:23).