Okla. Stat. tit. 22 § 324
The following oath must be administered to the foreman of the grand jury:
You, as foreman of this grand jury, shall diligently inquire into, and true presentment make, of all public offenses against this state, committed or triable within this county (or subdivisions), of which you shall have or can obtain legal evidence. You will keep your own counsel, and that of your fellows, and of the state, and will not, except when required in the due course of judicial proceedings, disclose the testimony of any witness examined before you, nor anything which you or any other grand juror may have said, nor the manner in which you or any other grand juror may have voted on any matter before you. You shall present no person through malice, hatred, or ill will, nor leave any unpresented through fear, favor or affection, or for any reward, or the promise or hope thereof; but in all your presentments, or indictments, you shall present the truth, the whole truth, and nothing but the truth, according to the best of your skill and understanding. So help you God.
Okla. Stat. tit. 22, § 324