The great news is that Jesus is our righteousness. And, unlike us, he is perfect!
Romans 3:20-26
20 Therefore by the deeds of the law no flesh will be justified in His sight, for by the law is the knowledge of sin.
21 But now the righteousness of God apart from the law is revealed, being witnessed by the Law and the Prophets,
22 even the righteousness of God, through faith in Jesus Christ, to all and on all who believe. For there is no difference;
23 for all have sinned and fall short of the glory of God,
24 being justified freely by His grace through the redemption that is in Christ Jesus,
25 whom God set forth as a propitiation by His blood, through faith, to demonstrate His righteousness, because in His forbearance God had passed over the sins that were previously committed,
26 to demonstrate at the present time His righteousness, that He might be just and the justifier of the one who has faith in Jesus.
Romans 5:17
17 For if by one man's offence death reigned by one; much more they who receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.)
1 Corinthians 1:30-31
30 But of Him you are in Christ Jesus, who became for us wisdom from God--and righteousness and sanctification and redemption--
31 that, as it is written, "He who glories, let him glory in the Lord."
Philippians 1:11
11 being filled with the fruits of righteousness which are by Jesus Christ, to the glory and praise of God.
Because the perfect righteousness of Christ is imputed to the believer, they are accepted by God (Ephesians 1:6); for only perfect righteousness will do. God will accept nothing less. It is the deluded Christian who thinks that in their daily living they can ever match the perfection of Christ's righteousness which has never at any point ever turned toward sin. No human can say the same. Every saved person has a history of sin that keeps them from ever being able to offer God truly perfect righteousness - not like the sinless Saviour possesses and as God requires. And this is why the news of the righteousness of Christ being imputed to us by faith is such great news! It lifts from us the impossibility of the burden of meeting God's perfect standard by our own inevitably corrupt effort. We are made perfect as our Father in heaven is perfect, not by dint of how we live, but by our being in Christ, clothed in his perfect, unchanging righteousness! What wonderful news for those believers who are laboring under the false notion that their acceptance with God has to do with their performance rather than with what Christ has done for them as their Saviour!
Does this mean a Christian can live in sin? Of course not. But it does mean the fear, and legalism, and inevitable hypocrisy that the sinless perfection doctrine engenders can be avoided and in their place a joyful, Christ-centered confidence in one's adoption into God's family can be instituted.
Romans 5:20
20...But where sin abounded, grace abounded much more,
Philippians 3:12-15
12 Not that I have already attained, or am already perfected; but I press on, that I may lay hold of that for which Christ Jesus has also laid hold of me.
13 Brethren, I do not count myself to have apprehended; but one thing I do, forgetting those things which are behind and reaching forward to those things which are ahead,
14 I press toward the goal for the prize of the upward call of God in Christ Jesus.
15 Therefore let us, as many as are mature, have this mind...
1 John 1:9
9 If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.