Scope of Practice

"What business is it of mine to judge those outside the church?  Are you not to judge those inside?  God will judge those outside.  'Expel the wicked person from among you.'"  1 Corinthians 5:12-13 (NIV)
As a licensed massage practitioner, part of my job involved recognizing conditions such as surface changes indicative of skin cancer for which a client should be referred to a doctor.  Ironically, though, it is illegal for an LMP to diagnose.  Contradictory though it may seem, it was required to recommend that a suspicious spot be seen by a dermatologist, but not allowed to mention the spot may be cancerous.  Diagnosing falls within a medical doctor's scope of practice, but not a massage practitioner's.
As Christians we are in a similar situation.  If another believer is out of line, we are supposed to do our part to bring that person back, as in Matthew 18 and Galatians 6.  But it is outside our scope of practice to pass judgment on people who don't hold themselves to our beliefs. While we should be vigilant to recognize unhealthy attitudes and actions in others and guard ourselves against those things, it's not our job to correct people who aren't believers.  Our job is to pray, be examples of Christ to them, and let the Holy Spirit do His convicting work.
"But as for you, continue in what you have learned and have become convinced of, because you know those from whom you learned it, and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Jesus Christ."  2 Timothy 3:14 (NIV)