138. Abetment of act of insubordination by soldier, sailor or airman.- Whoever abets what he knows to be an act of insubordination by an officer, soldier, 1[ sailor or airman], in the Army, 2[ Navy or air Force], of the 3[ Government of India], shall, if such act of insubordination be committed in consequence of that abetment, be punished with imprisonment of either description for a term which may extend to six months, or with fine, or with both.