What does the Bible say about Christ being a substitute for sin?

The concept of Christ as our substitute is central to the gospel. In 2 Corinthians 5:21, it is stated that God made Him, who knew no sin, to be sin for us, so that we might become the righteousness of God in Him. This means that Jesus, being completely sinless, took upon Himself the sins of His people, allowing them to exchange their sinful state for His righteousness. This substitution is necessary because one sinner cannot effectively substitute for another sinner; it requires a sinless sacrifice to bear the weight of sin and judgment.