The ancient world was divided by slaves and free persons.  Christians were to use their freedom to become God’s slave.  “Act as free men, and do not use your freedom as a covering for evil, but use it as bondslaves of God” 1 Peter 2:16 (NASB).  We will all be the slave of something or someone.  The genius of Christian choice is that we can choose our Master.  Our good Master, the Lord Jesus, brings us into true freedom.  He sets us free from the slavery to sin (Rom 6-8).  He brings us into “the glorious liberty of the children of God” (Rom 8:21).