In the present imperfect, sinful state, true and total perfection is not possible, as we are still under sin's law, our flesh that is. That is why the Christian needs the benefits of the ransom sacrifice to cover over where he fails. The righteousness of the Christian is not his own or of himself, it is attributed to him by God through the ransom. This doesn't mean that we cannot make progress or changes however, as we are told to strip off the old personality and put on the new. But total perfection is beyond our ability in our imperfect state. And, under the law, if one failed in one area, it was a failure to keep the Law, and meant condemnation, therefore the continual sacrifices were offered for sins. Our sacrifice is Jesus Christ, the Lamb of God.
"But now apart from law God’s righteousness has been revealed, as the Law and the Prophets bear witness, yes, God’s righteousness through the faith in Jesus Christ, for all those having faith. For there is no distinction. For all have sinned and fall short of the glory of God, and it is as a free gift that they are being declared righteous by his undeserved kindness through the release by the ransom paid by Christ Jesus. God presented him as an offering for propitiation through faith in his blood. This was to demonstrate his own righteousness, because God in his forbearance was forgiving the sins that occurred in the past. This was to demonstrate his own righteousness in this present season, so that he might be righteous even when declaring righteous the man who has faith in Jesus." Romans 3:21-26.
God attributes righteousness to those with faith in Jesus Christ, even though, and while, they are in an imperfect sinful state:
"Where, then, is the boasting? There is no place for it. Through what law? That of works? No indeed, but through the law of faith. For we consider that a man is declared righteous by faith apart from works of law." Romans 3:27, 28