Before performing their official duties, military judges, members of a general and special courts-martial, trial counsel, assistant trial counsel, defense counsel, assistant defense counsel, reporters, and interpreters shall take an oath to perform their duties faithfully. The adjutant general shall adopt rules prescribing the form of the oath, the time and place of the taking of the oath, the manner of recording, and whether the oath must be taken for all cases in which official duties must be performed or for a particular case. The rules may provide that an oath to perform duties faithfully as a military judge, trial counsel, assistant trial counsel, defense counsel, or assistant defense counsel may be taken at any time by any judge advocate or legal officer, or other person certified to be qualified or competent for the duty, and that once taken the oath need not be taken again each time the person is detailed to that duty.