What vow has king Arthur made?

King Arthur has made a vow to uphold justice and protect the realm, often symbolized by his commitment to the ideals of chivalry and the protection of the weak. This vow is central to his role as the leader of the Knights of the Round Table, where he seeks to create a just society. Additionally, Arthur is dedicated to searching for the Holy Grail, representing the pursuit of divine truth and enlightenment.