An oath of obligation, often called ‘word of honor’ is bond to temporal or secular authority. Only the will of the swearer is what holds this bond together. Any violation of the sworn word and the character suffers the typical results for violating a code of conduct. The Bondsman/Bannerman Oath is a typical example of this type, given to a lord, institution, brotherhood, etc. It is typical of the type of principles and scope of a Code of Conduct (an act of defined Transgression).
This presents a good opportunity for adding Character Story elements to the Character.