1 John 5:8
And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.
But if he will not hear you, then take with you one or two more, that in the mouth of two or three witnesses every word may be established.
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.
2 Corinthians 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.
1 Timothy 5:19
Against an elder receive not an accusation, unless before two or three witnesses.
He that despised Moses' law died without mercy under two or three witnesses:
At the mouth of two witnesses, or three witnesses, shall he that is worthy of death be put to death; but at the mouth of one witness he shall not be put to death.