What did Moses write concerning the righteousness that comes from the Law?...

The person who chooses to obey what God has said will live by God’s ordinances.

Ye shall therefore keep my statutes, and my judgments: which if a man do, he shall live in them: I am the Lord (Leviticus 18:5).

See, I have set before thee this day life and good, and death and evil (Deuteronomy 30:15).