10 GCA § 63720.8: Oaths.

(a) Before performing their respective duties, military judges, members of general and special court-martial, trial counsel, assistant trial counsel, defense counsel and assistant or associate defense counsel, reporters, and interpreters shall take an oath to perform their duties faithfully. The form of the oath, the time and place of the taking thereof, the manner of recording the same and whether the oath shall be taken for all cases in which these duties are to be performed or for a particular case, shall be as prescribed by the Guam Judge Advocate General. The Guam Judge Advocate General may provide that an oath to perform faithfully duties as a military judge, trial counsel, assistant trial counsel, defense counsel, or assistant or associate defense counsel may be taken at any time by a judge advocate or other person certified to be qualified or competent for the duty, and if such an oath is taken it need not again be taken at the time the judge advocate, or other person is detailed to that duty.

(b) Each witness before a court-martial shall be examined under oath.