This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong; it cannot perjure itself; it cannot be wholly absent. Only its interpretation can err.
Oath definition, a solemn appeal to a deity, or to some revered person or thing, to witness one's determination to speak the truth, to keep a promise, etc.: to testify upon oath. See more. Dictionary.com
Divine oath[edit] Usually oaths have referred to a deity significant in the cultural sphere in question. The reciter's personal views upon the divinity of the aspects considered sacred in a predictated text of an oath may or may not be taken in to account.