The following oath shall be administered to all bailiffs attending grand juries:
"You do solemnly swear that you will diligently attend the grand jury during the present term and carefully deliver to that body all such bills of indictment or other things as shall be sent to them by the court without alteration, and as carefully return all such as shall be sent by that body to the court. So help you God."
OCGA § 15-12-69