How do we know that Jesus' death was a sacrifice for sin?

The death of Jesus is presented in the New Testament as a once-for-all sacrifice for sin. He is called the Lamb of God in John 1:29, indicating His role as the true sacrificial lamb whose death atones for the sins of His people. This concept reaches its apex in Hebrews 10:10, which states that we have been sanctified through the offering of the body of Jesus Christ once for all. By His sacrifice, Jesus fulfills and supersedes the Old Testament sacrificial system, pointing to His death as the ultimate means of reconciling sinners to God.