John 8:17

and also in your law it hath been written, that the testimony of two men are true;

Deuteronomy 17:6

By the mouth of two witnesses or of three witnesses is he who is dead put to death; he is not put to death by the mouth of one witness;

Matthew 18:16

and if he may not hear, take with thee yet one or two, that by the mouth of two witnesses or three every word may stand.

Deuteronomy 19:15

'One witness doth not rise against a man for any iniquity, and for any sin, in any sin which he sinneth; by the mouth of two witnesses, or by the mouth of three witnesses, is a thing established.

1 Kings 21:10

and cause two men -- sons of worthlessness -- to sit over-against him, and they testify of him, saying, Thou hast blessed God and Melech; and they have brought him out, and stoned him, and he dieth.'

John 10:34

Jesus answered them, 'Is it not having been written in your law: I said, ye are gods?

John 15:25

but -- that the word may be fulfilled that was written in their law -- They hated me without a cause.

2 Corinthians 13:1

This third time do I come unto you; on the mouth of two witnesses or three shall every saying be established;

Galatians 3:24

so that the law became our child-conductor -- to Christ, that by faith we may be declared righteous,

Galatians 4:21

Tell me, ye who are willing to be under law, the law do ye not hear?

Hebrews 10:28

any one who did set at nought a law of Moses, apart from mercies, by two or three witnesses, doth die,

1 John 5:9

If the testimony of men we receive, the testimony of God is greater, because this is the testimony of God that He hath testified concerning His Son.

Revelation 11:3

and I will give to My two witnesses, and they shall prophesy days, a thousand, two hundred, sixty, arrayed with sackcloth;

Treasury of Scripture Knowledge

Bible References

Also

John 10:34
Jesus answered them, 'Is it not having been written in your law: I said, ye are gods?
John 15:25
but -- that the word may be fulfilled that was written in their law -- They hated me without a cause.
Galatians 3:24
so that the law became our child-conductor -- to Christ, that by faith we may be declared righteous,
Galatians 4:21
Tell me, ye who are willing to be under law, the law do ye not hear?

That

Deuteronomy 17:6
By the mouth of two witnesses or of three witnesses is he who is dead put to death; he is not put to death by the mouth of one witness;
Deuteronomy 19:15
'One witness doth not rise against a man for any iniquity, and for any sin, in any sin which he sinneth; by the mouth of two witnesses, or by the mouth of three witnesses, is a thing established.
1 Kings 21:10
and cause two men -- sons of worthlessness -- to sit over-against him, and they testify of him, saying, Thou hast blessed God and Melech; and they have brought him out, and stoned him, and he dieth.'
Matthew 18:16
and if he may not hear, take with thee yet one or two, that by the mouth of two witnesses or three every word may stand.
2 Corinthians 13:1
This third time do I come unto you; on the mouth of two witnesses or three shall every saying be established;
Hebrews 10:28
any one who did set at nought a law of Moses, apart from mercies, by two or three witnesses, doth die,
1 John 5:9
If the testimony of men we receive, the testimony of God is greater, because this is the testimony of God that He hath testified concerning His Son.
Revelation 11:3
and I will give to My two witnesses, and they shall prophesy days, a thousand, two hundred, sixty, arrayed with sackcloth;

General references

Numbers 35:30
whoso smiteth a person, by the mouth of witnesses doth one slay the murderer; and one witness doth not testify against a person -- to die.
Deuteronomy 17:6
By the mouth of two witnesses or of three witnesses is he who is dead put to death; he is not put to death by the mouth of one witness;