How do we know that Jesus is the true Lamb of God?

Jesus is identified as the true Lamb of God in both the Old and New Testaments. In John 1:29, John the Baptist famously declares Jesus as the Lamb of God who takes away the sin of the world. The sacrificial lamb must be without blemish, paralleling Jesus' sinless life—1 Peter 1:19 states that He was a lamb without spot or blemish. Furthermore, Jesus' crucifixion and resurrection fulfill the types and shadows of the Passover lamb in Exodus. The blood that He shed signifies not just an atoning sacrifice, but the perfect and complete fulfillment of the sacrificial system established in the Law.