The following is based somewhat on Scripture, somewhat on personal experience and somewhat on common sense.
When you think a fellow Christian is in sin and you want to address it:
- Check your heart and motivations. Is your desire to rescue someone who is straying, or is there an ulterior motive?
- Purify yourself. Unless you are without sin, your confrontation will be hypocritical.
- Do it now. If you indeed believe someone is in sin, delay could be dangerous.
- Keep confrontation small, do it in person. Don’t involve uninvolved people. Engage as few people as necessary; this allows greater opportunity for restoration.
- Be gentle. God is the ultimate Judge; harshness is a weapon only He may wield.
- Stay humble. Remember that you are also flesh and prone to failure.
- Assume misunderstanding. Give the benefit of the doubt that imperfect communication has misrepresented the issue.
- Seek to heal. Judgement is not the goal, repentance, forgiveness, reconciliation and restoration is the goal.
- Offer mercy. Treat others better than they deserve.
- Offer grace. Don’t treat others as they deserve.
These are simple ideas on how to do something we must be good at, whether we are on the receiving end or giving end. If we are not effective at this, the entire Church will suffer.
Supporting Scriptures:
Galatians 6:1-2 “Brothers, if anyone is caught in any transgression, you who are spiritual should restore him in a spirit of gentleness. Keep watch on yourself, lest you too be tempted. Bear one another’s burdens, and so fulfill the law of Christ.”
Matthew 18:15 “If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother.”
Luke 17:3 “Pay attention to yourselves! If your brother sins, rebuke him, and if he repents, forgive him.”
James 5:19-20 “My brothers, if anyone among you wanders from the truth and someone brings him back, let him know that whoever brings back a sinner from his wandering will save his soul from death and will cover a multitude of sins.”
Thoughts on Life and Leading 