 They contrast this with "just servitude" in which a metaphysical distinction is made between owning a person as an object, and only owning the work of that person.In practical terms a person could be bought sold or exchanged as a form of "just servitude" subject to certain conditions.Slavery for debt was typically legally a different matter under both pre-Christian and Christian legal systems; it might be only for a period, and the owner typically did not have the right to sell the slave without his agreement, and had other restrictions.