In his days Judah shall be saved, and Israel shall dwell safely: and this is his name whereby he shall be called, The Lord Our Righteousness. — Jeremiah 23:6
Today, we tend to define righteousness as that which is morally acceptable or which conforms to rules of conduct. But the Biblical usage has a far deeper meaning and implies a covenant relationship with God.
Righteousness is more than a character trait of God. The people of the Old Testament saw God's righteousness as His actions done in fulfillment of His covenant for His glory. God tells us, "I am the Lord, who exercises kindness, justice and righteousness on earth, for in these I delight" (Jeremiah 9:24). We are not simply to know that God is righteous, but we are meant to experience His righteousness.