All other civil officers, elected by the people or appointed to any civil office, unless otherwise provided, shall take and subscribe an oath substantially as follows:
I, ........................, do solemnly swear that I will support the Constitution of the United States and the Constitution of the State of Iowa, and that I will faithfully and impartially, to the best of my ability, discharge all the duties of the office of .................... (naming it) in (naming the township, city, county, district, or state, as the case may be), as now or hereafter required by law.