Matthew 18:16

but, if he hear you not, take with you yet one or two, that at the mouth of two witnesses or three, every word may be established.

John 8:17

And in your law also it has been written, 'The testimony of two men is true.'

2 Corinthians 13:1

This is the third time I am coming to you. At the mouth of two witnesses, and of three, shall every word be established.

1 Timothy 5:19

Against an elder receive not an accusation, except on the testimony of two or three witnesses.

Hebrews 10:28

Anyone, having set aside Moses' law, dies without mercy on the testimony of two or three witnesses;

1 John 5:7-8

And the Spirit is He Who beareth witness, because the Spirit is the Truth:

Revelation 11:3

And I will give to My two witnesses, and they shall prophesy a thousand two hundred and sixty days, clothed in sackcloth."

Treasury of Scripture Knowledge

Summary

But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established.

Bible References

That in

John 8:17
And in your law also it has been written, 'The testimony of two men is true.'
2 Corinthians 13:1
This is the third time I am coming to you. At the mouth of two witnesses, and of three, shall every word be established.
1 Timothy 5:19
Against an elder receive not an accusation, except on the testimony of two or three witnesses.
Hebrews 10:28
Anyone, having set aside Moses' law, dies without mercy on the testimony of two or three witnesses;
1 John 5:7
And the Spirit is He Who beareth witness, because the Spirit is the Truth:
Revelation 11:3
And I will give to My two witnesses, and they shall prophesy a thousand two hundred and sixty days, clothed in sackcloth."