Deuteronomy 19:15

One witness is not enough to convict someone of a crime, offense, or sin he may have committed. Cases must be settled based on the testimony of two or three witnesses.

Numbers 35:30

Those accused of murder may be found guilty and put to death only on the evidence of two or more witnesses. The evidence of one witness is not sufficient to support an accusation of murder.

Matthew 18:16

If he does not listen to you, take one or two more people with you. Two or three witnesses may prove every case.

2 Corinthians 13:1

This is now the third time that I am coming to visit you. The testimony of two or three witnesses must uphold an accusation. (Deuteronomy 19:15)

Deuteronomy 17:6

On the evidence and testimony of two witnesses or three witnesses, he who is to die shall be put to death. He shall not be put to death on the evidence of one witness.

John 8:17

It is written in your law that the witness of two men is true.

1 Timothy 5:19

Do not offer an accusation against an elder, except at the mouth of two or three witnesses.

Hebrews 10:28

He that despised Moses' Law died without mercy under two or three witnesses.

1 Kings 21:10

Get two good-for-nothing persons to come before him and give witness that he has been cursing God and the king. Then take him out and have him stoned to death.

1 Kings 21:13

The two good-for-nothing persons came in and took their seats before him and gave witness against Naboth, in front of the people. They said: Naboth has been cursing God and the king. Then they took him outside the town and had him stoned to death.

Matthew 26:60-61

They failed, even though a number of false witnesses came.

Revelation 11:3-7

I will give power to my two witnesses, and they will prophesy a thousand two hundred and sixty days, clothed in sackcloth.

Treasury of Scripture Knowledge

Summary

One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established.

Bible References

At the mouth

Deuteronomy 17:6
On the evidence and testimony of two witnesses or three witnesses, he who is to die shall be put to death. He shall not be put to death on the evidence of one witness.
Numbers 35:30
Those accused of murder may be found guilty and put to death only on the evidence of two or more witnesses. The evidence of one witness is not sufficient to support an accusation of murder.
1 Kings 21:10
Get two good-for-nothing persons to come before him and give witness that he has been cursing God and the king. Then take him out and have him stoned to death.
Matthew 18:16
If he does not listen to you, take one or two more people with you. Two or three witnesses may prove every case.
Matthew 26:60
They failed, even though a number of false witnesses came.
John 8:17
It is written in your law that the witness of two men is true.
2 Corinthians 13:1
This is now the third time that I am coming to visit you. The testimony of two or three witnesses must uphold an accusation. (Deuteronomy 19:15)
1 Timothy 5:19
Do not offer an accusation against an elder, except at the mouth of two or three witnesses.
Hebrews 10:28
He that despised Moses' Law died without mercy under two or three witnesses.
Revelation 11:3
I will give power to my two witnesses, and they will prophesy a thousand two hundred and sixty days, clothed in sackcloth.

General references

Numbers 35:30
Those accused of murder may be found guilty and put to death only on the evidence of two or more witnesses. The evidence of one witness is not sufficient to support an accusation of murder.
Deuteronomy 17:6
On the evidence and testimony of two witnesses or three witnesses, he who is to die shall be put to death. He shall not be put to death on the evidence of one witness.
John 7:51
Does our law convict a man without first hearing from him to find out what he has done?