Wikipedia
Loyalty oath
A loyalty oath is an oath of loyalty to an organization, institution, or state of which an individual is a member.
In this context, a loyalty oath is distinct from a pledge or oath of allegiance. It is an affirmation by which a person signs a legally binding document or warrant.
Usage examples of "loyalty oath".
How are you coming on getting your men to take the new loyalty oath?
She heard the thoughts beneath his solemn words: there was no telling what trouble a Touched brat might bring on a soldier who had forsworn his loyalty oath to his king and his birth-vow of conduct as a member of the soldiers' caste.
Miles thought the loyalty oath was redundant, since neither academic could have held their current posts without having taken one previously.