All witnesses, including grand jurors, shall be bound to answer fully, and shall not be answerable for the testimony so given in any way, except for the crime of perjury committed in giving such evidence. When a grand juror has been fully examined as to his qualifications to sit, and has answered under oath that he is qualified, and has been received by the court and permitted to act, his incompetency shall not thereafter be shown as a ground of objection to any indictment returned by that grand jury. R.L.1910, § 5782.
Oklahoma Legal Code