It is not acting on command in itself that makes someone a slave, but rather the reason for so acting. ...A slave is someone obliged to obey commands from a master which look only to the advantage of the master.
Gist of Idea
Slavery is not just obedience, but acting only in the interests of the master
Baruch de Spinoza (Tractatus Theologico-Politicus , 16.10)
So if I forcibly enslaved you, and then only commanded things which were for your own good, that would not be slavery? If the master feeds the slave, is that not part of the slavery? Most jobs might count as slavery by this account?
Spinoza,Benedict de: 'Theological-Political Treatise', ed/tr. Israel,Jonathan [CUP 2007], p.201