"Either the doers of the law will be justified as 2:13 says, or the deeds of the law do not justify as 3:20 says. You can't have it both ways." Like I mentioned before, these are letters from which the reader is only receiving information from one side. A grammatical survey is only one small step in the hermeneutical "process." In other words, there are calculations that are incomplete. At first glance, it may appear that the two Romans verses contradict each other, but further hermeneutical analysis will reveal that this letter was written to both Jews and Gentiles, and that the audience didn't seem aware that the Law places people in a position that they are unable to fight against because of the sin nature in humans. Even Jesus says in John 7:19, when speaking to Jewish contemporaries that oppose Him: "Has not Moses given you the Law? Yet none of you keeps the Law..." (NIV; NIV citations for readability purposes). Paul knew this, and this understanding hit home because he himself claims that he is "circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; in regard to the law, a Pharisee" (NIV). In other words, Paul is a Hebrew trained well in theology. And again, Paul calls himself the chief of sinners in 1 Tim. 1:15-16: "Christ Jesus came into the world to save sinners—of whom I am the worst. But for that very reason I was shown mercy so that in me, the worst of sinners, Christ Jesus might display his immense patience as an example for those who would believe in him and receive eternal life" (NIV). So, even though Paul was a man in a very high spiritual position (a pharisee), he could not uphold the Law. You can see a taste of his struggle in Romans 7, because there is a desire to be righteous, which is part of the purpose of the Law (Romans 7:7).
With these things in mind, Paul is saying in 2:13 that those who will obey the Law will be declared righteous. That is clear. In Romans 3:20, It might not be so clear "at first glance:" He is saying that NO ONE is capable of holding or keeping the Law. Romans 6:23 says that the wages of sin is death. Do you know what that means? It means that if you sin, you die! The statistics are serious... the death rate since the beginning of history is 1/1! Romans 5:12 says that death comes to all people, because ALL sinned. What is sin? It is breaking God's Law according to Paul. Now if one were born, not into sin, and lived a perfect life, then He would not need salvific grace through Jesus. The problem is, Jesus is the only One to live a sinless life! In other words, it IS impossible to obey the Law. James explains that once you break the Law, THATS IT (See James 2:10)! You are now a Law breaker in need of salvation through Jesus.
In Galatians 3:11, Paul is saying that "Now it is evident that no one is justified before God by the law (because it is impossible for one to not be a Lawbreaker), for 'The righteous shall live by faith (Since they cannot keep the Law and must put their trust in Jesus for salvation)."
Habakkuk on the other hand, was under the sacrificial code of the OT. One thing is for sure, if you break the Law, there must be an atonement (which is blood; Levi 17:11) in order to restore a right relationship with God. This blood sacrifice was performed frequently as you might imagine. People are at their core, sinners and selfish. Hence the phrase, "sinful nature." Observe what the Psalmist wrote: "The Lord looks down from heaven on all mankind to see if there are any who understand, any who seek God. All have turned away, all have become corrupt; there is no one who does good, not even one" (NIV Psalm 14:2-3).
In any event, there aren't any interpolations that change the message in any way, and this is known because there are well over 5000 manuscripts of the NT of which are compared and contrasted which results in what is called the majority text. The M-text gives Bible interpreters the advantage of producing an interpretation that reports a functionally equivalent message to the reader. In other words, the message doesn't change because God's word lasts forever (Isaiah 40:8 and 1 Peter 1:25; see also Isaiah 55:11).
Written by Nace Howell through the grace of the Lord Jesus