How do we know that Jesus is the substitute for our sins?

The doctrine of substitution underscores that Jesus bore the penalty for the sins of His people. In Isaiah 53:5, it states, 'He was wounded for our transgressions; he was bruised for our iniquities.' This prophecy points forward to Jesus' atonement on the cross, where He directly fulfilled the role of the sacrificial Lamb. In John 17:9, Jesus intercedes for His elect, distinctly praying not for the world but for those given to Him by the Father, affirming His mission to save those whom He chose before the foundation of the world. This highlights His role as a specific substitute, made evident through His suffering, death, and subsequently, the resurrection.