Righteousness was a Hebrew legal concept that meant, “right standing before God” as in a court of law. It carried the picture of two positions in a lawsuit, one “not in the right,” and the other, “in the right” or “righteous” before God. It was primarily a relational term. Not only that, but in both Testaments, the righteous man is the man who is said to “live by faith,” not by perfect good deeds (Hab. 2:4; Rom. 1:17). So righteousness does not mean “moral perfection” but “being in the right with God because of faith.”
