How do we know that Jesus' sacrifice truly forgives sins?

The truth of Jesus' sacrifice lies in its sufficiency as satisfaction for God's holy justice. The resurrection of Christ serves as God's affirmation that all requirements for the forgiveness of sins have been met. Acts 5:30-31 states that this same Jesus, whom they crucified, is the one whom God raised, thus confirming His authority to grant repentance and forgiveness of sins. Faith in Christ rests upon His accomplished work, proving that His sacrifice did not merely make salvation possible, but actually achieved it for His people.