Each trustee shall, within ten days after the trustee’s appointment or election, take an oath of office that, so far as it devolves upon the trustee, the trustee will diligently and honestly administer the affairs of the board of trustees, and that the trustee will not knowingly violate or willingly permit to be violated any of the provisions of law applicable to the system. The oath shall be subscribed to by the member making it and certified by the officer before whom it is taken and shall be immediately filed in the office of the lieutenant governor.