“I suspect that one of the reasons why there are so many exhortations in the New Testament for Christians to love other Christians is because this is not an easy thing to do. Many fellow Christians will appear to be, at least initially or to the immature, “little enemies.” To put the matter differently, if Christians love Christians, it is not exactly the same thing as what Jesus has in mind when he speaks rather dismissively of tax collectors loving tax collectors and pagans loving pagans. What he means in these latter cases is that most people have their own little circle of “in” people, their own list of compatible people, their friends. Christian love…must go beyond that to include people outside the group. The objects of our love must include those who are not “in”: it must include enemies.
Ideally, however, the church itself is not made up of natural “friends.” It is made up of natural enemies. What binds us together is not common education, common race, common income levels, common politics, common nationality, common accents, common jobs, or anything of the sort. Christians come together, not because they form a natural collocation, but because they have been saved by Jesus Christ and owe him a common allegiance. In the light of this common allegiance, in light of the fact that they have all been loved by Jesus himself, they commit themselves to doing what he says – and he commands them to love one another. In this light, they are a band of natural enemies who love one another for Jesus’ sake.”