Question: "Why does Christ's righteousness need to be imputed to us?"
Answer: In His Sermon on the Mount, Jesus uttered these words: “You therefore must be perfect, as your heavenly Father is perfect” (Matthew 5:48). This comes at the end of the section of the sermon where Jesus corrects His listeners’ misunderstanding of the Law. In Matthew 5:20, Jesus says that, if His hearers want to enter into the kingdom of heaven, their righteousness must exceed that of the Pharisees, who were the experts in the Law.
Then, in Matthew 5:21–48, He proceeds to radically redefine the law from mere outward conformity, which characterized the “righteousness” of the Pharisees, to an obedience of both outward and inward conformity. He says, “You have heard it said, but I say unto you” to differentiate between the way people heard the law taught from how Jesus is reinterpreting it. Obeying the law is more than simply abstaining from killing, committing adultery, and breaking oaths. It’s also not getting angry with your brother, not lusting in your heart, and not making insincere oaths. At the end of all this, we learn that we must exceed the righteousness of the Pharisees, and that comes from being perfect.
At this point, the natural response is “But I can’t be perfect,” which is absolutely true. In another place in Matthew’s Gospel, Jesus summarizes the Law of God with two commandments: Love the Lord your God with all your heart, soul, mind, and strength and love your neighbor as yourself (Matthew 22:37–40). This is certainly an admirable goal, but has anyone ever loved the Lord with all his heart, soul, mind, and strength and his neighbor as himself? Everything we do, say, and think has to be done, said, and thought from love for God and love for neighbor. If we are completely honest with ourselves, we have to admit that we have never achieved this level of spirituality.
The truth of the matter is that, on our own and by our own efforts, we can’t possibly be perfect as our heavenly Father is perfect. We don’t love God with all our heart, soul, mind, and strength. We don’t love our neighbors as ourselves. We have a problem, and it’s called sin. We are born with it, and we cannot overcome the effects of it on our own. Sin radically affects us to our core. Sin affects what we do, say, and think. In other words, it taints everything about us. Therefore, no matter how good we try to be, we will never meet God’s standard of perfection. The Bible says that all of our righteous deeds are like a “polluted garment” (Isaiah 64:6). Our own righteousness is simply not good enough and never will be, no matter how hard we try.
That’s why Jesus lived a perfect life in full obedience to the law of God in thought, word, and deed. Jesus’ mission wasn’t simply to die on the cross for our sins but also to live a life of perfect righteousness. Theologians refer to this as the “active and passive obedience of Christ.” Active obedience refers to Christ’s life of sinless perfection. Everything He did was perfect. Passive obedience refers to Christ’s submission to the crucifixion. He went willingly to the cross and allowed Himself to be crucified without resisting (Isaiah 53:7). His passive obedience pays our sin debt before God, but it is the active obedience that gives us the perfection God requires.
The apostle Paul writes, “But now the righteousness of God has been manifested apart from the law, although the Law and the Prophets bear witness to it—the righteousness of God through faith in Jesus Christ for all who believe” (Romans 3:21–22). Through our faith in Christ, the righteousness of God is given to us. This is called “imputed” righteousness. To impute something is to ascribe or attribute something to someone. When we place our faith in Christ, God ascribes the perfect righteousness of Christ to our account so that we become perfect in His sight. “For our sake he made him [Jesus] to be sin who knew no sin, so that in him we might become the righteousness of God” (2 Corinthians 5:21).
Not only is Christ’s righteousness imputed to us through faith, but our sin is imputed to Christ. That is how Christ paid our sin debt to God. He had no sin in Himself, but our sin is imputed to Him so, as He suffers on the cross, He is suffering the just penalty that our sin deserves. That is why Paul can say, “I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me” (Galatians 2:20).
By having the righteousness of Christ imputed to us, we can be seen as sinless, as Jesus is sinless. It is not, therefore, our perfection, but His. When God looks at the Christian, He sees the holiness, perfection, and righteousness of Christ. Therefore, we can say with confidence, “I am sinless, as Jesus is sinless.”