Mich. Comp. Laws § 32.617
An officer of the national guard shall take and subscribe to the following oath of office: "I ..................... do solemnly swear (or affirm) that I will support and defend the constitution of the United States and the constitution of the state of Michigan, against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I will obey the orders of the president of the United States and of the governor of the state of Michigan; that I make this obligation freely, without any mental reservation or purpose of evasion, and that I will well and faithfully discharge the duties of the office of ....................... in the national guard of the United States and of the state of Michigan, upon which I am about to enter." The officer shall take this oath within 10 days after his appointment and unless he does so is deemed to have declined his office and his appointment may be vacated.
MCL 32.617