Atonement is central to Christian theology, and without the cross we do not have Christianity. Much of the New Testament is devoted to explicating what happened on the cross of Christ, and the atonement was necessitated by the problems that sin brought to our relationship with God (Rom. 3:21–26). To understand the atonement, therefore, we must first understand how our transgressions affect our relationship with our Creator.
First, as a result of sin, we have incurred a debt to God. Since God is the Creator and our Sovereign King, He has the absolute right to impose obligations on us. God first imposed His law on us in Eden, commanding Adam to obey Him perfectly by not eating the forbidden fruit (Gen. 2:15–17). Adam stands in a special relationship to the rest of humanity. He is the federal head or representative of the entire human race (except Jesus), which means that his response to God’s command is reckoned as our response to God’s command. Adam’s disobedience, therefore, is our disobedience, and when Adam sinned, we incurred an infinite debt against the Lord (Rom. 3:23; 5:12–21; 1 Cor. 15:22). No sinner can pay this debt, for it takes someone of infinite worth to satisfy this charge against us. Christ, however, could pay this debt because of His infinite worth as the Son of God. His sacrifice pays the debt for Adam’s sin and for all of our individual transgressions when we trust in Him alone. He becomes our new federal head, and we are counted righteous in Him (2 Cor. 5:21).
Sin also puts us at enmity with God. It has broken our relationship with Him and has made us His enemy (Hos. 1:2; Rom. 3:23). We have wronged God by our sin and destroyed the relationship, and the only way to restoration is through Christ the Mediator. Despite our having broken this bond with our Creator, God sent His Son to atone for the sins of His people. In Christ, we are God’s children, we have peace with God, and our relationship with Him is restored (John 3:16; Rom. 5:1; 8:1–17; Eph. 1:3–6).
In our sin, we have also committed a crime against God and are worthy of the penalty of hell. As our righteous Judge, God cannot merely dismiss this penalty. It must be paid, though we cannot pay it. But God in His grace will accept a substitute. Christ bore the righteous curse of hell on the cross so that we could receive His steadfast love and mercy (Rom. 3:21–26; Gal. 3:10–14). God’s righteousness and love meet at the cross (Ps. 85:10).