“When Peter came to Antioch, I opposed him in public because he was clearly wrong”. 

Gal 2:11 GNB 

It is not always easy to decide what is right and what is wrong. Sometimes it is clear, but not always. Many issues are complicated but because of emotions, past traditions, the need to honour some people and the fear of upsetting others, being misunderstood or of things backfiring, people find themselves in moral dilemmas. And often people are just unable to think things through thoroughly. 
Peter was the appointed leader of the early church. But he was an older man and was steeped in Jewish traditions. He had gone to the city of Antioch in the north of Syria where there was a strong church developing. At first he had meals with some Gentile Christians which was against the strict provisions of the Jewish law. Then some pro-Jewish people arrived from Jerusalem, presumably criticized him, and he withdrew from these contacts. Paul knew this kind of discrimination was wrong and was against the decision that had previously been reached by the church to include Gentile Christians as fully-fledged members. So Paul, not being the leader, and being a much younger person, confronted Peter and told him how wrong he was. It must have been an embarrassing experience for Peter. But it was right for the church, even though it helped to drive the Christian church and the Jewish religion even further apart. 
Strive to understand what is right and wrong in complicated issues. Then have the courage to stand for what is right, even when significant persons are taking the opposite view and the tide appears to be going against you. Paul did just that. Martin Luther did. So did John Wesley. 

Lord, help me to be strong enough to fight for what is right.