'Righteously' in the Bible

If you know that He is absolutely righteous, you know [for certain] that everyone who practices righteousness [doing what is right and conforming to God’s will] has been born of Him.

Dear children, let no one lead you astray. The man who acts righteously is righteous, just as He is righteous.

By this we can distinguish God's children and the Devil's children: no one who fails to act righteously is a child of God, nor he who does not love his brother man.