Sin is any lack of conformity to the moral law and character of God, either in act, disposition or state [Romans 5:13-14; Romans 7:22; James 4:11-12]. Sin is called an act (Romans 7:19), a disposition/state (Jeremiah 17:9; Psalm 51:5; Romans 7:8-10, 17), conscious or subconscious thought (Matthew 5:27-28; Matthew 15:19), an affection (Exodus 20:17; 1 John 2:15-17), an omission (James 4:17), an involuntary act (Luke 12:48; 2 Peter 3:5) or any combination of these. Sin is any being, action, or disposition that is unlike God.
Sin entered the universe as a result of the fall of Satan (1 John 3:8), and sin entered the human race as a result of the fall of Adam (Romans 5:12). Personal, individual sin originates from the human heart (Mark 7:21-23; James 1:14) and is rooted in selfishness and self-autonomy (Isaiah 14:12-14; 2 Thessalonians 2:3-4; Deuteronomy 6:4-5). God permitted sin to enter the universe through the free, willful, and uncoerced act of Satan and subsequently of Adam (non-constraining determinism), and it was right for God to do so though the reason will forever remain a mystery to finite creatures (Judges 18:25; Deuteronomy 29:29; Proverbs 25:2).
Adam’s first sin, the one sin of the one man, comprehended the whole human race. Adam acted as the representative of the race, and his sin is immediately imputed to the entire race (original sin – Romans 5:12-19). Depravity, condemnation, and death came to the race as a result of Adam’s sin. Hereditary depravity (complex of sinful attributes) issues from the judicial solidarity between Adam and all men (Romans 5:19). Since Adam’s sin is imputed immediately to the race, all men are born totally depraved (Romans 3:23; Ephesians 2:1). Depravity is total in that it has penetrated and affected the entire race (Galatians 3:22; Romans 3:10; Psalm 14:1-3; 1 Kings 8:46) and the whole of man’s being (Isaiah 1:6; Ephesians 4:17-19). Depravity has penetrated man’s body (Romans 8:10; Ephesians 4:19) resulting in entropy and death, man’s mind (Titus 1:15; Romans 8:5-7; 1 Corinthians 2:14), man’s will (John 8:34; Jeremiah 13:23) and heart (Jeremiah 17:9). Man, therefore, has the native capability of committing the most vile sins (Romans 1:18ff; Romans 3:10-18). When unregenerate man does “good” via common grace (Genesis 6:3; Romans 2:14-15; Matthew 7:11), it is for selfish purposes and not for God’s glory (Isaiah 64:6; Matthew 6:5; Proverbs 21:4). Thus, man has no possible means of salvation or recovery within himself and is utterly incapable of meriting God’s favor or contributing to his salvation (Matthew 19:25-26; Romans 1:18; Romans 7:18; Ephesians 2:1, 8; Titus 3:5; Hebrews 12:2).
Infant damnation is not a necessary corollary to original sin. In light of the principles regarding personal responsibility (Deuteronomy 1:39; Isaiah 7:14-16), relative innocence (1 Corinthians 14:20; Matthew 18:3), accountable works (Romans 2:5-6; Revelation 20:11-12), and unconditional election (Ephesians 1:1-5), God is free within the confines of His personal attributes and plan to unilaterally regenerate infants moments prior to death based on the merits of Christ’s atonement; and, thereby one is able to provide genuine comfort to grieving parents (Jeremiah 1:5; Luke 1:15, 44, 41; 2 Samuel 12:23; cf. 2 Samuel 18:33; 1 Thessalonians 4:13).