How do we know Jesus' substitutionary death is effective for salvation?

The effectiveness of Jesus' substitutionary death is rooted in the principle of divine justice. According to Acts 5:31, Peter proclaims that God exalted Jesus to be a Prince and a Savior, enabling Him to give repentance and the forgiveness of sins. This indicates that Christ's sacrificial death fulfills the requirements of justice by bearing the penalty for the sins of His people. Romans 3:25 states that God presented Christ as a sacrifice of atonement, thus making it just for God to forgive sinners who place their trust in Him. This transaction assures that believers are not merely pardoned, but their sins are completely paid for through Christ's blood.