Do you have someone in your life that rubs you the wrong way? Someone with whom you just can't get along? I think we all do, the problem is, that at times, the problem is not really them it is us or our perception of them. God brings people into our lives for so many reasons, and in many cases, they are there for our benefit whether we appreciate it or not. God can work all things for our good. Paul writes this to a church trapped with pagan, anti-Christian forces all around them.
"If it is possible, as much as depends on you, live peaceably with all men." Romans 12:18
We all have people in our lives that are difficult to get along with and if truth be told we all have people in our lives that find us difficult to get along with. God does not give us a pass to simply ignore those people. Paul is writing here that "if possible" means "while potentially difficult it is still doable."
Our peace is not generated by us but instead by God. His challenge is live peaceably because He has given you peace, part of the fruit of the Spirit is peace. Paul's challenge is, therefore, being that you possess God's peace in your life do your best to maintain that peace in all your relationships.
Paul's phrase "all men" is literally everyone regardless of economics, politics, race, heritage, religion, background, or culture, be at peace with everyone, no-one is excluded. Jesus expects us to give our best effort to be at peace with everyone.
What does that look like? If someone absolutely drives you crazy and the relationship can not be reconciled, stay away from the person to keep the peace. Sometimes the best things we can do is get out of God's way and allow Him to work. If we keep fighting, then neither of us are at peace. If it doesn't seem that you can be reconciled, don't give up so easily, especially if they are a brother or sister in the Lord. We need to allow the Holy Spirit to work in them and in us to come to a place of peace. If we have to continue to be around someone that we can not be at peace with, then limit your time with them, keep your peace when you are with them, always praying for God's peace to come for both of you.
You are the one who is required by the Lord, as a Christian to be at peace as much as it applies to you. Don't give up on people easily, keep loving and do your best to keep your eyes on Jesus not them and at best you may win a friend at worse you may come to a healthy detente with someone who is completely different than you. He is your peace. Don't allow it to get stolen from you. You have the power regardless of the situation to be at peace.