Occasionally stories are told about someone being sentenced for a crime when suddenly another person steps up and says, "I will take the punishment for him." Most such stories are not based in fact. But the NT teaches that Jesus, in His ;, death, has taken the penalty for our sin upon Himself.
Scripture teaches that all humanity is tainted and corrupted by sin, both because of the sin of our forefather Adam (Rm 5:12-21) and because we ourselves are all sinners (Eph 2:1-3). God, as the righteous Judge, cannot and will not simply overlook sin, since sin violates His nature and brings destruction to the perfect world He created. God would be unjust simply to say, "Oh well, boys will be boys." Instead, sin must be punished, and since all of us have broken God's law, we rightly deserve full punishment. Yet, amazingly, Jesus came to take our punishment upon Himself.
The NT speaks of Jesus' death providing forgiveness in at least three ways. First, Jesus' death was a sacrifice for our sins. Christ fulfills the OT sacrificial system in being both high priest and sacrifice (Heb 5-10). On the Day of Atonement, animals were killed before the altar and the blood was sprinkled on the mercy seat in the most holy place. Under that seat were tablets of stone upon which had been written the Ten Commandments. Looking down from heaven God could see the law, but when the sacrificial blood was sprinkled, the law-as reminder of the people's sin-was covered. Without the shedding of blood, there is no forgiveness of sin (Heb 9:22).
Second, the NT speaks of Christ's death as a "propitiation" for our sin (Rm 3:2126). This word, hilasmos, carries the meaning of "an offering satisfying God's wrath toward sin," yet remarkably God Himself provides this offering. When Jesus died on the cross, He cried out, "My God, My God, why have You forsaken Me?" (Mt 27:46). The Father was pouring out His wrath because "He made the One who did not know sin to be sin for us, so that we might become the righteousness of God in Him" (2 Co 5:21).
Third, and related to both points already made, the Bible speaks of Christ's death as a substitution. Jesus did not come to be served but to serve and "to give His life-a ransom for many" (Mk 10:45). Jesus "gave Himself for our sins to rescue us from this present evil age" (Gl 1:4). Isaiah's predictions of a coming Suffering Servant are fulfilled in the death of Jesus, who "was pierced because of our transgressions, crushed because of our iniquities ... and the Lord has punished Him for the iniquity of us all" (Is 53:5-6). He died in our place.
By faith, and faith alone, we receive the forgiveness Christ provides through His humiliating and painful death. The result? Eternal life (Eph 2:3-10).
Extracted from the Apologetics Study Bible.