Does Romans 12:18 require Christians to live peaceably with everyone no matter what?
No. Romans 12:18 says peace should be pursued "if it be possible" and "as much as lieth in you," recognizing that in a devil's world it is not always possible. It does not obligate believers to let an unbeliever cheat them or to refuse lawful recourse, such as hiring a lawyer.
Les explains that Romans 12:18's command is qualified: "If it be possible, as much as lieth in you, live peaceably with all men." Because we live in a devil's world, peace is not always possible. He illustrates with a class member who thought that as a Christian he could not take a deadbeat contract buyer to court. Les asked whether the buyer was a fellow believer or in the same church body. The man said no, he was not even a Christian. Les therefore told him to "get after him," saying it was his prerogative to hire a good lawyer and that he did not have to starve because a crook failed to fulfill his obligations. The man had already done everything he could to obtain payment, yet was destitute. Les showed him this verse.
If it be possible, as much as lieth in you, live peaceably with all men.
More Questions
Is it true that a Christian just has to let people do whatever they want and never argue?
Romans 12:18 is a loophole against the idea that a Christian must simply let people do whatever they want to him and is in no position to argue because he is a Christian.