In order to confirm the validity of truth, the Bible requires that there be two or more witnesses: (Deuteronomy 17:6 “The one condemned to die is to be executed on the testimony of two or three witnesses. No one is to be executed on the testimony of a single witness.”
Deuteronomy 19:15 ““One witness cannot establish any iniquity or sin against a person, whatever that person has done. A fact must be established by the testimony of two or three witnesses.”
