Noah Had One and Was Heir to the Other

If we turn, however, to Heb. 2 we there find that Noah "became heir of the righteousness which is by faith." Notice the language well. In the first place he is an heir to it, which implies two things—the one that he does not have it yet, and the other that he has not worked for it—no man can work for what he inherits. Secondly, this righteousness is by faith. Turning to Rom. 3:22 (so perfectly does Scripture explain itself), we see clearly that the righteousness which is by faith is the righteousness of God. We thus see that Noah lived in one righteousness, and became heir to another. The reason he was only heir to the righteousness of God is explained in Rom. 3:25, where it is shown that God could not declare His righteousness, in passing over Noah's sins, until an adequate propitiation had been made by the death of Christ.
By considering this case we see that the righteousness in which Noah stands (or will stand) before the throne, is the righteousness of God, as seen in the perfect work of Christ, whereas that in which he lived and glorified God on earth was his own practical righteousness.
In Eph. 4:24 we read that the new man is created anew in "righteousness and true holiness," or practical RIGHTEOUSNESS and SANCTIFICATION. Walking in newness of life (Rom. 6:4) includes these two things (see Luke 1:75), as is seen in the end of Rom. 6, when both are connected as the result of a godly walk. (vv. 19, 22).
Practical Righteousness
Taking PRACTICAL RIGHTEOUSNESS first, we will briefly consider what Scripture says on the subject. In 2 Cor. 6:14, we notice this remarkable fact: it is the first thing mentioned in separation from evil. It is also the very first thing that we are called to follow after, (1 Tim. 6:11), and also again in 2 Tim. 2:22. Thus on three separate occasions it occupies the first place. In fact, it is the first of the three things of which the Kingdom of God is said to consist practically. (Rom. 14:17.) In 2 Cor. 6:7, it is generally described as the Christian's armor (consider this expression well), and in Eph. 6 as the breastplate, or that which protects the vital parts. Practically, it is said to give a good conscience (1 Peter 3:16), which is also of all importance. God's eyes are over the practically righteous man (1 Peter 3:12), and that His ears are open to his cry, is seen not only here, but also in James 5:16, where the effectual, fervent prayer of a righteous man availeth much. Not in one of the passages that have been alluded to does the word "righteous" refer to our standing before God (or what is common to all Christians, and what each possesses in full perfection), but to the individual acts and character in which none is perfect, and no two are alike. Turning to Eph. 5, we find further that this righteousness is the fruit of the light (Eph. 5:9, according to the best versions), an important point to which we shall refer again. In 1 John 3:7, we find that Christ only is the standard of it, and in verse 10 that it is is a proof of the new birth.