In order to be truly free one must become a slave to Christ.
The world seduces us with slavery and calls it freedom. Christ calls us to become his slaves, to take up the easy yoke, which is the only freedom.
- Michael Card
Paul often called himself “a slave to Christ”
...This letter is from Paul, Jesus Christ’s slave,...Romans 1:1;
...Paul, the slave of God ...Titus 1:1;
....I, Paul, the slave of Christ....Ephesians 3:7