'Righteousness' in the Bible

Little children (believers, dear ones), do not let anyone lead you astray. The one who practices righteousness [the one who strives to live a consistently honorable life—in private as well as in public—and to conform to God’s precepts] is righteous, just as He is righteous.

By this the children of God and the children of the devil are clearly identified: anyone who does not practice righteousness [who does not seek God’s will in thought, action, and purpose] is not of God, nor is the one who does not [unselfishly] love his [believing] brother.