One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sins: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established.
All Commentaries on Deuteronomy 19:15 Go To Deuteronomy 19
Augustine of Hippo
AD 430
Therefore if a people composed of a great multitude was found a false witness, how must it be understood, “In the mouth of two or three witnesses every word shall stand,” except that in this way. The Trinity, in which is unending stability of truth, was revealed through a mystery. Do you want to have a good case? Have two or three witnesses, the Father and the Son and the Holy Spirit. .