The Apostle Paul explains it this way: “God made Christ, who never sinned, to be the offering for our sin, so that we could be made right with God through Christ.” (2 Corinthians 5:21 NLT)
Christ’s substitutionary sacrifice fulfills a prophecy that Isaiah uttered some 800 years earlier: “The Lord laid on Him the iniquity of us all.” (Isaiah 53:6b NKJV)
Theologians have often referred to this as Jesus’ “vicarious” suffering; that is, He suffered in our place. As our substitute, He took the punishment that we deserved.
-- Clinton E. Arnold in an article entitled “The Ultimate Sacrifice” in Discipleship Journal, Sep/Oct 2006