The prophet Isaiah foretold the death of Christ as our substitute. He died in our place and for our sins. It was prophesied centuries before it happened. "He was led as a lamb to the slaughter" (Isaiah 53:7). The Bible is such an amazing book. Inspired by the Holy Spirit, the Bible declares by the foreknowledge of God, Christ crucified centuries before it comes to pass.
See Jesus on the cross as the Lamb of God, dying for the sins of the world. John the Baptist pointed to Jesus as the fulfillment of the prophecy. He said, "Behold! The Lamb of God who takes away the sin of the world" (John 1:29). That is to say, Jesus died as the substitute for sinners.
Jesus, like the passover lamb in the Old Testament, died in the place of others. He is every believer's substitute at the cross. He took our sins and our judgment. He shed his blood and poured out his life on our behalf. He died that we may have life eternal. Our sin debt was paid by the Lamb of God.
Do you see Jesus as your substitute? Can you say by faith, that on the cross he took my place? The testimony of faith is made sure by the Holy Spirit working grace in your heart. Has it happened in your heart? If so, you see the Lamb dying, knowing that he was the sacrifice for all of your sins.