Paul was ironically referring to false teachers that at first impression appear to be Christians…but it’s only a guise. And that’s what makes false teachers that superficially look or act like Christians so dangerous. They may have all the “Christian” terminology down pat, and enamor everyone with their eloquent speech, but what comes out of their mouths is not the Gospel Message. Rather, it’s divisive and contrary to doctrine. People like this teach of a corrupted Jesus, and their lives are in the flesh, so don’t be deceived. (Romans 16:17)