Impute /imˈpyo͞ot/ verb - to reckon to one what does not belong to him
Much debate throughout the history of the church orbits around this one word: imputation. The doctrine of imputation asserts that at salvation, when you or I as a sinner trusts Jesus Christ alone for salvation, all our our sin is reckoned—imputed—to His account, and His righteousness is reckoned—imputed—unto our account. So that in the same act, Jesus on the cross became the greatest sinner by imputation, and we became the righteousness of Christ by imputation. 2 Cor. 5:21 "For our sake He made Him to be sin who knew no sin, so that in Him we might become the righteousness of God." As saved sinners we stand before God Almighty not on the merits of our own righteousness, but on the merits of Jesus Christ alone. This imputation is not infusion. Infused righteousness is the Roman Catholic doctrine that acknowledges that righteousness is given to the believer as a gift from God. A gracious gift even. However, that righteousness only inheres in the believer to the extent that they maintain it and cooperate with it. The problem with this, is that it confuses justification—the judicial act of having our sins forgiven and being declared righteous by faith alone, with sanctification—the progressive act where we are renewed in the whole man dying unto sin and living unto righteousness. These are two distinct things, and to combine them together is to lose all hope of ever seeing our Heavenly Father's face. There is no gospel (good news) if imputation is not a reality
If eternal life with God is in the balance, waiting to see if I cooperate with His righteousness in order to be accepted in the beloved, I am ruined. That is not hyperbole. There is absolutely no hope for my soul if ultimate salvation depends on my my contribution of righteousness As the Psalmist has said "Enter not into judgment with your servant, for no one living is righteous before you." Psalm 143:2 Our God is not a God who will accept the smallest degree of unrighteousness. Anything less than perfect righteousness is spiritual pollution and that is exactly what we possess "All our righteous deeds are like a polluted garment." Isaiah 64:6 This is part of the gospel that many of us modern Christians fail to see. God requires absolute perfection in order for us to be received into His heaven. The standard is not softened simply because we cannot achieve that perfection. God does not grade on the curve. If He were to bend the eternal law of righteousness and receive into His family persons who were polluted, He would be denying His own glory. God cannot be good at the same time while calling evil good. He must judge righteously or else He is not righteous.
This is why the cross is so central to Christianity, and more specifically imputation. If Jesus didn't die for all of my sins, I will be judged for the remaining ones. This is bad news. James tells us that the smallest sin is a violation of the whole law (James 2:10). So if Jesus didn't pay for every single sin, it is as if He didn't pay for any. Likewise if Jesus' righteousness is not imputed to my account completely, so that the Father sees His merits when He looks at me, I will be an abomination to His glory. I have hidden faults in all my best deeds. My most spiritual moments have dark closets and undisclosed motives and insincere intentions actively working through them. Should God accept those? Should God be so easily pleased that I simply put forth my best effort and call it good after that? Brothers and sisters, that is the Mormon gospel. That is the gospel of Islam, the gospel of Rome, the gospel of this world. If God were to accept that type of righteousness, He is not God. Any god who doesn't require the defendants in his courtroom to be acquitted completely and to be declared absolutely righteous is a god who is not worthy of worship. That god despises his own worth-ship so how could he be worthy of our worship? The doctrine of imputation then is not just our only hope for heaven, it is the only hope for God to remain God. Not only do we lose the gospel if we shed imputation, we lose the glory of God.