Before testifying, every witness shall be required to declare that the witness will testify truthfully by oath or affirmation, administered in a form calculated to awaken the witness's conscience and impress the witness's mind with the duty to do so.
Tenn. R. Evid. 603
Advisory Commission Comments.
Witnesses have already been required to take an oath or affirmation. T.C.A. § 24-1-101 [repealed], third sentence, is similar to the rule.