Why is believing in Christ's atonement crucial for Christians?

The atonement of Christ is the cornerstone of salvation in sovereign grace theology. It is through Christ's sacrificial death that believers receive forgiveness of sins and reconciliation with God, as demonstrated in 1 Peter 2:24, which states, 'Who his own self bare our sins in his own body on the tree.' Without acknowledgment and faith in this atonement, there is no true life; 'He that hath the Son hath life; and he that hath not the Son of God hath not life' (1 John 5:12). The implications are massive; this belief transforms one’s entire life, leading to a life abiding in Christ, filled with hope and security found in His finished work.