Ephesians 1:7–8 gives the answer: “In him [i.e., Jesus Christ] we have redemption through his blood, the forgiveness of sins.”
Redemption and forgiveness are powerful images. Redemption portrays a slave set free. On several occasions, Paul refers to us as “slaves to sin” whom God has liberated through Christ (e.g., Rom 6:6, 16, 17, 20; 7:14, 25). Forgiveness portrays a debt being canceled. We are debtors to sin and owe God more than we can pay, but God has canceled our debt. According to Paul, redemption and forgiveness come at a great cost go God, namely, the death of his Beloved Son. We have redemption and forgiveness “through his blood.”
Why did Christ have to die for our redemption and forgiveness? Why couldn’t God just declare us free? Why couldn’t he simply cancel our debt? John Stott points to the answer when he writes:
The problem of forgiveness is constituted by the inevitable collision between divine perfection and human rebellion, between God as he is and us as we are. The obstacle to forgiveness is neither our sin alone, nor our guilt alone, but also the divine reaction in love and wrath toward guilty sinners. For, although indeed “God is love,” yet we have to remember that his love is “holy love,” love which yearns over sinners while at the same time refusing to condone their sin. How, then, could God express his holy love—his love in forgiving sinners without compromising his holiness, and his holiness in judging sinners without frustrating his love?
Through the cross. Christ’s death is redemptive—it forgives our sins—because it satisfies God’s holiness (punishing sin) and expresses his love (providing salvation). As Romans 3:25–26 puts it: “God presented him [Jesus Christ] as a sacrifice of atonement, through faith in his blood. He did this to demonstrate his justice, because in his forbearance he had left the sins committed beforehand unpunished—he did it to demonstrate his justice at the present time, so as to be just and the one who justifies those who have faith in Christ.” Paul states the same truth using a simpler image in 2 Corinthian 5:21: “God made him who had no sin to be sin for us, so that in him we might become the righteousness of God.” He did the same in Galatians 3:13: “Christ redeemed us from the curse of the law by becoming a curse for us.”
So, when we talk about redemption and forgiveness, we should always do so by talking, in the same breath, about the cross. We have redemption and forgiveness “through his blood.” And when we pray, we should always pray “in Christ’s name,” asking God to see us through the eyes of his Beloved Son, “who loved us and gave himself up for us” (Eph. 5:2).
The cross, then, solves the problem of forgiveness, and makes us confident that when we pray for grace through Christ, God will answer our request (Rom. 8:31–34).