Deuteronomy 19:15New Revised Standard Version (NRSV)
Law concerning Witnesses
15 A single witness shall not suffice to convict a person of any crime or wrongdoing in connection with any offense that may be committed. Only on the evidence of two or three witnesses shall a charge be sustained.
Deuteronomy 19:15New International Version (NIV)
15 One witness is not enough to convict anyone accused of any crime or offense they may have committed. A matter must be established by the testimony of two or three witnesses.