I suspect it will be possible to treat each other with love only if we are able to conceive doing so as a moral obligation that is absolute, something we owe others because of their personhood, bearing no relation to whether we like them or nor. My wife puts it this way: every encounter with another human being should inspire in us a powerful sense of awe. Why? Because that other human being, whatever his or her strengths, weaknesses, and simple complexities, is also a part of God's creation. We should be struck with awe at the fact that we are face to face with a part of God's work. It is one of those propositions that, once stated, seems like a truth we should have seen all along--but somehow it takes someone of uncommon wisdom to point it out.
To enter into the presence of another human being, then, is to enter the presence of God in a new and different way. We are admonished in the psalm to come into His presence with thanksgiving (Psalm 95:2), not with suspicion, self-seeking, or disrespect. The great theologians Karl Barth and Martin Buber both arrived at this point along their different paths: our obligation is to see God in everyone, not merely as possibility, but as reality. So whenever we mistreat others, we are abusing our relationship with God. And awe alone does not capture what we owe. We should encounter others with a sense of gratitude, for here is a fresh and different corner of God's creation--or, for the secular-minded, a new and different human being. We should be grateful to be traveling where we have not been before.
I'll leave that without comment, except wow that gives me a lot to work on.
I also recommend Stephen Carter's Culture of Disbelief to anyone who is interested in religion and public life. It was published in 1993 (I think) but is still relevant. I think most of my blog readers would find it provocative, even if you don't agree with everything in it. By the way, Carter is a professor at YLS, but I read and appreciated Culture of Disbelief long before we knew where we'd end up (and possibly before I even met Justin, I'm not sure).