When God created man in His own image (Gen. 1:26-27), He did also give man all that was necessary for life: God's blessing was upon him (Gen. 1:28), a place of residence, the Garden of Eden (Gen. 2:8), food to eat (Gen. 1:29; 2:16-17), dominion over the earth (Gen. 1:28), and a companion as a helper (Gen. 2:18-25). God commanded man to be fruitful and multiple (Gen. 1:28) and to not eat of the tree of knowledge of good and evil (Gen. 2:16-17), this only is revealed as forbidden to man.
Man had the freewill to obey or disobey God and a warning of consequence, if man choose to disobey: death on the very day he disobeyed (Gen. 2:17). Man was innocent, without the knowledge of good and evil (Gen. 3:22-24), prior to eating the forbidden fruit. Man did reject God's command and ate of the forbidden tree (Gen. 3:6) and they, Adam and Eve, did experience spiritual death (Gen. 2:17; Eph 2:1,5; Col 2:13), dying also a physical death at a later time (Gen. 5:4-5; Rom. 5:12; 6:23) and were condemned to wait in hell for the day of judgment (2 Pet. 2:9; Rev. 1:18; 20:13), then comes the second death (Rev. 21:8), separation from God (2 Thess. 1:9). Additionally, mankind and creation were punished (Gen. 3:14-19; Rom. 8:22-23) and all of Adam's descendants were born, not in the image of God, as Adam was, rather the image of fallen man (Gen. 5:3), only now being similar to God's image (Jas. 3:9) and suffering the same death as Adam (Rom. 5:12; Eph 2:1,5; Col 2:13). God then removed Adam and Eve from the Garden so they would not eat also the of the tree of life and live forever in their fallen state (Gen. 3:22-24).
God did and is just in condemning us all through Adam's sin (Rom. 5:18) because God knows all (Isa. 46:10) and is just (Deut. 32:4). God, before the foundation of the world, knowing all things (1 Jn. 3:20), knew His creation would exercise their God given freewill and reject Him (Gen. 3:6), thereby dying to God, an immediate spiritual death (Gen. 2:17; Eph 2:1,5; Col 2:13). God in His wisdom, before the foundation of the world, did choose to send Christ (1 Pet. 1:18-20), His only Son (Jn. 3:16; Rom. 8:32), to be our Lord (Rom. 10:9-10) and Savior (Jn. 4:42), to pay the price of sin (Rom. 6:23; Gal. 2:21) for us (Rom. 5:11-12; 2 Cor. 5:18-19) that we could not pay ourselves (Gal. 2:16, 21; Eph. 2:8-10) and foretold of such to His creation (Gen. 3:15). Knowing also, none would choose Christ's redemptive act on our own (Rom. 3:11; 8:7), God therefore, in His love and mercy (Jn. 3:16; Rom. 9:16), chose, before the foundation of the world to saved some (Rom. 9:13; 2 Thess. 2:13; 2 Tim. 1:9), not according to our works (Rom. 9:11-16; Eph. 2:8-10), rather by the work and faith of Christ (Rom. 3:21-26; 2 Cor. 5:18-19; Heb. 9:15) and God's sovereign will and purpose (Eph. 1:4-5; 3:9-11). Thereby giving us a new life (2 Cor. 5:17; Gal. 6:15) and rescuing us from hell (2 Pet. 2:9) and the second death, which is to come (Rev. 21:8).
Because of sin, we died to God (Gen. 2:17; Eph 2:1,5; Col 2:13) and walk the earth spiritually dead, unable to receive God's Word (1Cor 2:14), and blinded to God by the god of this world, Satan (Acts 26:18; 2 Cor. 4:4). So prophesy may be fulfilled (Isa. 6:9-10; 44:18), we remain in darkness until God quickens us, making us alive through His gift of salvation, (Jn. 5:21; 6:63; Eph. 2:1, 5; Col 2:13) to those He has chosen, (Jer. 1:5; Rom. 9:11-23; Eph. 1:4-5; 3:9-11; Gal. 1:1; 2 Thess. 2:13; 1 Tim. 1:1; 2 Tim. 1:9); it is not our choice (Jn. 1:12-13; 14:17; 15:16, 19; Jas. 1:17-18). After which we, by His grace (Acts 15:11; Eph. 2:5, 8; 2 Tim. 1:9), hear the voice of the Shepherd (Jn. 10:16, 27) through His Word (Jn. 20:31) and the voice of His servants (Mk. 16:15-16; Rom. 10:14), become saved and obtain eternal life (Mk. 10:30; Jn. 17:3; 1 Jn. 5:13, 20). Jesus confirmed these truths when He explained to His disciples why He spoke in parables: in seeing and hearing they will not perceive or understand, lest they be saved (Mk. 4:11-12, 33-34; Lk. 8:10; Jn. 12:37-41). God further confirmed this through Paul: the naturally minded do not receive Scripture (1Cor 2:14).
Once we are saved, we are new creatures in Christ (2 Cor. 5:17; Gal. 6:15), renewed in the knowledge of God who created us (Col. 3:10), freed from the blindness of Satan (Acts 26:18; 2 Cor. 4:4), restored again to a freewill to put on new man and put off old self (Eph. 4:22-24; Col. 3:8-9) and to do good works (Mt. 5:16; 1 Tim. 6:18; 1 Pet. 2:12); being slaves to the one whom we choose to obey (Matt. 6:24; Jn. 8:34; Rom. 6:14-16). When we do not follow the Spirit, He is grieved (Eph. 4:30; 1 Thess. 5:19) and our growth in Christ suffers until we confess (1 Jn. 1:9); when we follow the Spirit, He works through us to accomplish what God asks us to do (Rom. 8:4-13; Gal. 3:3; 5:16-17, 25). All who are saved, while we may struggle to live according to our calling (Rom. 7:14-25), will live a lifestyle of choosing to following the Spirit (Rom. 8:9; Gal. 5:25) with assurance of eternal life (Jn. 5:24; 1 Jn. 5:13, 20; 1 Pet. 1:3-5; Jude 24).
While believers cannot lose their salvation by someone taking us away from God (Jn. 10:29), nor by other outside forces (Rom. 8:35-39) or by sin (1 Pet. 1:5; 1 Jn. 1:9), or a lack of obedience to teach and/or obey God's commands (Mt. 5:19) because salvation is a gift (Jn. 3:16; Rom. 6:23), it is possible, as revealed in Scripture and by God's warning, for some to give up their gift of salvation by a willful act of their restored freewill (Col. 3:10; Heb. 10:26): if one were to subtract words from Scripture, God will take that one's part form the book of life (Rev. 22:19); if one was to commit the unforgivable sin of blaspheming the Holy Spirit (Mt. 12:31; Mk. 3:29) or if one were to denounce Christ, not merely denying to know Christ as a person as Peter did (Mt. 26:31-75), rather rejecting belief in Christ, who He is and what Christ has done. By such one would be exercising their renewed freewill and renewed knowledge of God (Col. 3:10) as a new creature in Christ (2 Cor. 5:17) to willfully (Heb. 10:26) reject God (2 Thess. 2:3; Heb. 6:4-6), after God has graciously given them eternal life (Jn. 10:28; Rom. 5:10; 6:23). Thereby, once having been enlightened by and becoming partakers with the Holy Spirit (Matt. 13:20-21; Mk. 4:16-17; Heb. 6:4-6), and then denouncing the faith, will be lost without any hope of repentance (Heb. 6:4-6; Rev. 3:5). Sadly, some have in the past and today fallen away with the number increasing greatly in the end time (1Tim 4:1; 2Thess 2:3). Many are called, few are chosen (Mt. 20:16; 22:14). Thus, Scripture is fulfilled.
However, thanks be to God, the elect (Mt. 24:31; Jn. 1:12-13; 17:2-3; Rom. 8:28-30; 9:11-16; 2 Tim. 1:9; 1 Pet. 1:2; Jas. 1:17-18; Jude 1) of God will endure, not choosing to forsake Christ, even to the end, for without God's intervention, even they, the elect, would reject Him (Mt. 24:22-24). Therefore, while all deserve hell and separation from God, salvation of any is by the mercy of God (Rom. 9:16; 1 Pet. 2:10). We, not knowing who God will save, proclaim salvation to all, knowing God's elect will hear His voice and come to Him (Jn. 10:16, 27).