The NIV 365-Day Devotional Reading PlanSampel

How could David be so certain of his own righteousness?

In the Old Testament, Israel could know God’s moral will for his people through the laws set forth in the covenant made at Mount Sinai (Ex 20:1 — 24:18; Lev 26:1 – 46; Dt 4:1 — 11:32). If David lived in a manner consistent with those covenant stipulations, he could legitimately speak of his righteousness.

David was not perfect by any means — a fact he readily acknowledged (Ps 51:1 – 19). But while it is a great sin to violate God’s law, the covenant provided a means by which confession, repentance, restitution and restoration to God and the community could take place. The sacrificial system outlined in Leviticus 1:1 — 7:38 provided the Israelites with a process by which to make amends to God and their neighbors when they sinned. But more important than sacrifice is a humble and penitent heart that casts itself entirely on the mercy of God (Ps 51:1,16 – 17). When we do this, God “imputes” righteousness to us — that is, he credits the perfect righteousness of Jesus Christ to us (2Co 5:21).

Taken from NIV Quest Study Bible