How should Christians relate to non-Christians?

Walter L. Bradley:

When I was appointed head of the mechanical engineering department of sixty-five professors in 1989, I began to have the opportunity for much more personal interaction with faculty in our department who worked in divisions other than my own. A faculty member named Clay asked for an appointment with me to discuss his request for a one- to two-year leave of absence, and I suggested that we have lunch at the faculty club. He explained that Gail had finished her degree in veterinary medicine and had gotten a job at the zoo in Portland, Oregon, and he wanted to go with her. As we visited, I asked him about his and Gail's relationship, how long they had been married, and if they had any children. He responded with some discomfort that he and Gail were not married but had lived together for six years. While this was known to some people in the department, he had apparently not wanted to share it with me, anticipating my disapproval since he knew I was an evangelical Christian. How would you have responded to such an opportunity?

I though a response indicating my Christian disapproval not only would be not very helpful to Clay but would reinforce his stereotype about evangelical Christians and his desire to keep a safe distance from them. Instead, I responded by telling Clay that I could understand how a person who did not believe in a God of revelation who had given specific guidance about how we should live our lives would find such an arrangement to be perfectly sensible. I indicated that society today seemed to affirm such alternative lifestyles. I went on to share that if indeed the Bible was the Word of God, then such an arrangement would prove to be unsatisfactory in the long run, however satisfactory it seemed to be in the short run. He seemed relieved by my response and immediately asked me to tell him more about why I thought the Bible was the Word of God and therefore should be used as a moral compass to get through life. We spent the rest of our lunch hour discussing this fundamental question, which was much more fruitful than arguing about whether he should or should not live with Gail out of wedlock. Until our friends accept the authority of Scripture, the primary questions to be discussed have to be those of God's existence and transcendence.

- Excerpted from p. 308 of Telling the Truth

The doesn't just end here, but here seems a good spot to leave off from. Let's just say that the relationship in question here didn't wind up working up.