Deuteronomy 19:15

19:15 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 a matter be established.
-World English Bible

Other Translation

19:15 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.
-King James Version