Texas Code of Criminal Procedure - CRIM P Art. § 20A.256. Witness Oath

Before each witness is examined, the foreperson or a person under the foreperson's direction shall administer the following oath to the witness: “You solemnly swear that you will not reveal, by your words or conduct, and will keep secret any matter about which you may be examined or that you have observed during the proceedings of the grand jury, and that you will answer truthfully the questions asked of you by the grand jury, or under its direction, so help you God.”