Deuteronomy 4:2

4:2 Do not add a thing to what I command you nor subtract from it, so that you may keep the commandments of the Lord your God that I am delivering to you.

Deuteronomy 4:5-6

4:5 Look! I have taught you statutes and ordinances just as the Lord my God told me to do, so that you might carry them out in the land you are about to enter and possess. 4:6 So be sure to do them, because this will testify of your wise understanding to the people who will learn of all these statutes and say, “Indeed, this great nation is a very wise people.”