Yogācārabhūmi-śāstra: Volume 34 (Part 41)

How, again, is impermanence to be contemplated through the aspect of separation from states? It should be understood that all conditioned things are impermanent based on two kinds of separation: internal and external. Regarding the impermanence based on internal separation: Suppose there is a person who was formerly a master, neither a slave nor a servant. He was able to enjoy things himself and to drive others to perform various tasks. Later, that person loses the state of being a master, along with the state of not being a slave or servant. Instead, he acquires the state of being another's slave and the state of being a servant. This separation from the state of being a master, etc., is called the impermanence of separation.