Christian freedom being lost by a return to bondage is a strong warning of Paul in Rom 6 and Gal 5.  “For you were called to freedom, brethren; only do not turn your freedom into an opportunity for the flesh, but through love serve one another” (Gal 5:13).  Individuals who are slaves to sin cannot remain free.  Ironically, those who are slaves to God and right (righteousness) stay free (see Rom 6:12-22).  Freedom is being Jesus’ slave.