Deut. 17: 6 At the mouth of two witnesses, or three witnesses, shall the matter be established.
John 8:17 It is also written in your law, that the testimony of two men is true.
Matthew 18:16 In the mouth of two or three witnesses every word may be established.
2 Corin. 13:1 This is the third time I am coming to you. In the mouth of two or three witnesses shall every word be established.