Deuteronomy 4:6

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.”

Deuteronomy 8:19

8:19 Now if you forget the Lord your God at all and follow other gods, worshiping and prostrating yourselves before them, I testify to you today that you will surely be annihilated.

Deuteronomy 19:15

19:15 A single witness may not testify against another person for any trespass or sin that he commits. A matter may be legally established only on the testimony of two or three witnesses.