Ambrosiaster : Whoever has been delivered from sin is truly free. The ancients used to say that anyone who acts unwisely is a slave. They called all wise men free, and all the unwise were slaves as far as they were concerned. In any case, even a free believer is a slave of Christ, for to be free from God is the greatest sin of all. — COMMENTARY ON PAUL'S EPISTLES John Chrysostom : 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. — Homily on 1 Corinthians 19 Oecumenius : Paul wants to show that slave and master are equal. We are all freedmen of Christ because he has set us free from the tyranny of Satan, and we are voluntary slaves of Christ because, having set us free, he led us into his own kingdom. — PAULINE COMMENTARY FROM THE GREEK CHURCH