righteousness (Greek dikaiosunē): In the first part of Romans, Paul uses this Greek word in a legal sense. It refers either to God’s action of placing people in a right relationship with himself or to the right standing believers receive because of Christ’s work (see, for example, 1:17; 3:21–22; 4:3, 5).
Here, Paul uses the same word in the way it is often used in the Old Testament. It means the right kind of behavior that God expects from his people.