I remember very well my mother warning me not to get caught in the middle of someone's dispute with another. She said it would not turn out well for me if I did. I must confess that this has happened to me on a few occasions, and she was right. I ended up embroiled in a controversy that had nothing to do with me in the end, but it spoiled my outlook on everything.
First and foremost, we should listen to them, and if possible, encourage them. Everyone needs a sounding board. We all need acceptance and a chance to be real with others. However, we also have to be careful not to pick up that friend's offense as though it were our own. Recognize that God may be at work in that person and we do not want to hinder God's efforts to mature them. In the flesh, we want to fix everything and everybody. Sometimes, we cannot do either. Yet there is something we can and should do.
We should take time to pray with that person and continue to lift them up in prayer each day. God is capable of healing the offense our friend feels. He is able to do what we cannot. Jesus said in Matthew 5:9: "Blessed are the peacemakers: for they shall be called the children of God." This is what we need to be doing on a daily basis. We are to be peacemakers. The last thing we want to be is a troublemaker in the household of God.
Jesus is the only burden bearer whose blood was shed to cover our sins. Therefore we know He is trustworthy to bring about a resolution to the dispute or offense our friend is feeling. If we choose to take their offense into our own hearts and make it our own, there are some sad consequences we will face. We become embittered towards the party that hurt our friend. This keeps us from being a peacemaker or reconciler that Christ has called us to be. We begin to look with a critical eye at everything the offending party does. I have seen this happen in the workplace where one employee poisons another co-worker's outlook towards the boss or a fellow employee. Going to work is no longer enjoyable. We find ourselves looking at the other party all the time and building a case against them. All of this drama only contributes to a negative atmosphere to work in and does little to bring people together. Christ has called us to live as lights in this world and not as agents of darkness. Therefore, like Jesus, let us be wise and not become embroiled in a dispute. Instead, pray for all involved that God would heal hearts remembering that Christ was wounded for us and our transgressions. He alone is the burden bearer. This will bring glory to the Father and peace to those involved.
Selah!