We are dead to sin and by nature children of wrath. Salvation is not a matter of reforming our behavior so that we are good enough to go to heaven when we die, but rather of trusting in the finished work of Jesus on our behalf. We are not saved by our faith; we are saved by Jesus (through faith). Even our faith is a gift from God; we bring nothing to the table except our sin.
The Scriptures use many images to describe what happened on the cross, including substitutionary atonement, victory over sin and death, and moral influence. Each of these models (and others) give facets of Jesus’ work, but none were meant to be exhaustive. Jesus died for us.
Faith is more than just intellectually assenting to certain facts about Jesus, but rather trusting in him to deliver us from sin and death. Faith is only possible through the work of the Holy Spirit and the proclaimed gospel. When we hear the gospel, the Holy Spirit calls us from death into life, but in his mercy and wisdom, God allows humans to resist this call of the Spirit.
Through faith, the believer is united to Christ so that what is true of Jesus becomes true of us. God then no longer sees the believer as who he or she is in himself or herself, but as he or she is “in Christ.” Jesus promises to bring to completion the work that he has begun in our hearts, so that believers can have assurance of their salvation.
Apart from the grace of God and the finished work of Jesus, human beings remain in sin and have no hope.
(Isaiah 64:6; Matthew 26:28; John 1:29, 3:7–18, 5:24; Acts 7:51, 13:39; Romans 3:25–26, 5:1, 6–9; 2 Corinthians 5:21; Galatians 3:13; Ephesians 1:3, 7, 2:8–9; Philippians 3:4–9; Titus 3:5; 1 Peter 1:18–19, 3:18; 1 John 5:11–12)