A more thorough explanation:

An oath of office is a promise made by an individual to uphold and fulfill certain requirements and obligations of a position they were either elected or appointed to. This promise is usually made in a formal ceremony and is a legal requirement for those who hold government positions.

For example, in the United States, the President must take an oath of office before assuming their duties. The oath is governed by Article II, Section 1, Clause 8 of the Constitution and requires the President to swear to "faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States."

Similarly, for any other government position except for the President, the oath of office is governed by 5 U.S. Code § 3331. This oath requires the individual to swear to "support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter."

These oaths of office are important because they ensure that those who hold government positions are committed to upholding the laws and values of their country. They also serve as a reminder that those in power are accountable to the people they serve.