Deuteronomy 19:15

One witness shall not stand against another, no matter what the sin or outrage may be. For every word shall stand by the mouth of two or three witnesses

Other versions

King James Version

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.

English Standard Version

"A single witness shall not suffice against a person for any crime or for any wrong in connection with any offense that he has committed. Only on the evidence of two witnesses or of three witnesses shall a charge be established.

New International Version

One witness is not enough to convict a man accused of any crime or offense he may have committed. A matter must be established by the testimony of two or three witnesses.