This book explores an alternative understanding of atonement in Paul’s undisputed letters. In doing so, it distinguishes Paul’s theology from later writings such as Deutero-Pauline letters, Pastoral letters, or Hebrews and interprets the cause of Jesus’s death differently. Traditionally, as we saw before, Jesus’s death has been understood as vicarious suffering, which deals with the guilt of sin, God’s punishment, God’s moral justice, or liberation from sin’s power. In an alternative understanding of the atonement, sin’s problem, or the fundamental issue for humanity is disobedience or unfaithfulness to God, which is the cause of estrangement between God and humanity. This problem or issue is resolved when one repents (change of a mind) through participating in Jesus’s faithfulness that ended up his crucifixion—a multifarious, climatic event that reveals God’s righteousness and Jesus’s grace. On one hand, God dealt with the past of humanity, infused with sins of disobedience, because of Jesus’s faithfulness and his sacrifice, and on the other hand, he opened a new path of reconciliation/atonement to those who participate in Jesus’s life and death. Often people think that Paul cares about Jesus’s death only, which is understood as no more than a vicarious sacrifice. Subsequently, they do not consider Jesus’s faithfulness and his obedience to God’s will that all humans need a recovery of faith. They seem to think that Jesus came to die for them. But if we read Paul’s undisputed letters, Paul’s view of Jesus’s death is deep and complex in that Jesus’s crucifixion is the result of his life-risking challenge to the wisdom of the world. What is needed is faithful living. The radical concept of atonement requires human participation in Jesus’s life and death. Jesus is the locus of reconciliation. His sacrifice is not required for atonement (reconciliation); it is unwanted yet unavoidable because of his testimony to God’s righteousness. We need an alternative view of atonement where sins are forgiven not because Jesus died for sinners but because they repent of their sins, looking to his cross and all his faithful journey toward God’s righteousness.