When you look at Romans 12 I appreciate that this verse finds itself in that chapter.
Think about it, verse 1 tell us to present our bodies as a living sacrifice.
Verse 2 tells us to not be conformed to this world. (We, believers, need to look totally different!)
Verses 3 to 8 give a list of spiritual gifts given to us in relationship to the body of Christ.
Then verse 9 - 17 says:
Love must be sincere. Hate what is evil; cling to what is good. Be devoted to one another in love. Honor one another above yourselves. Never be lacking in zeal, but keep your spiritual fervor, serving the Lord. Be joyful in hope, patient in affliction, faithful in prayer. Share with the Lord’s people who are in need. Practice hospitality.
Bless those who persecute you; bless and do not curse. Rejoice with those who rejoice; mourn with those who mourn. Live in harmony with one another. Do not be proud, but be willing to associate with people of low position. Do not be conceited.
Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everyone.
Then verse 18 tells us that whatever we can do, live peaceable with others in the body of Christ.
The world is watching Christians. I think disharmony, disunity, factions, church splits, divorce, arguments, and fights keep more people from coming to the the pure joy of a relationship with Christ than almost anything else.