Oath of office
an official promise by a person who has been elected to a public office to fulfill the duties of the office according to the law
An oath of office is an oath a person gains a higher position, usually in government or within a religious body. There are other positions in which people are supposed to take oaths as well, like in the military. When someone makes an oath, they make a promise to follow certain rules and guidelines of the position that they are taking. Some oaths of office are a statement of loyalty to a constitution or other legal text, to a person or other office holder. Under the laws of a state it may be considered treason or a high crime to betray a sworn oath of office. Oaths of office can be a public ceremony, like in the United States with presidential inauguration, or private.