John Chrysostom
Patristic
A.D. 347–407
“Next he adds also the cause; "For he that was called in the Lord being a bondservant, is the Lord's free man: likewise he that was called, being free, is Christ's bondservant." "For," saith he, "in the things that relate to Christ, both are equal: and like as thou art the slave of Christ, so also is thy master. How then is the slave a free man? Because He has freed thee not only from sin, but also from outward slavery while continuing a slave. For he suffers not the slave to be a slave, not even though he be a man abiding in slavery: and this is the great wonder. But how is the slave a free man while continuing a slave? When he is freed from passions and the diseases of the mind: when he looks down upon riches and wrath and all other the like passions.”