A matter came up at our Bible study regarding Matthew 18:15-17, dealing with people who have wronged us. "If your brother sins against you, go and show him his fault, just between the two of you. If he listens to you, you have won your brother over. But if he will not listen, take one or two others along, so that every matter may be established by the testimony of two or three witnesses. If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, treat him as you would a pagan or a tax collector."
The key word I'm stuck on is "brother." Some felt strongly that this referred to the world as a whole, others that it referred only to fellow believers. I was in a similar situation many years ago, and sought the help of my pastor after following the first two steps. The person who wronged me did not believe as we did. My pastor said that person was not my "brother" and I was "done" attempting to resolve this according to these biblical instruction.
So, then, who is my brother?
I checked many other versions of the Bible looking for clarification. Most use "brother" but a few use "fellow believer," "another believer," or "another one of my followers."
In Matthew 12:48-50, Jesus says, "Who is my mother, and who are my brothers?" Pointing to his disciples, he said, "Here are my mother and my brothers. For whoever does the will of my Father in heaven is my brother and sister and mother."
My conclusion is that we are called to use kindness and truth and integrity in dealing with everyone, but our relationships to other believers are special and set apart, and the instructions in the Bible referring to our "brothers" is not wholly applicable to everyone. The relationship between believers is crucial, treasured, and holy.