One of my favorite quotes from one of the most explosive chapters of any book of any author I have ever read.
“We make our friends; we make our enemies; but God makes our next-door neighbour. Hence he comes to us clad in all the careless terrors of nature; he is as strange as the stars, as reckless and indifferent as the rain. He is Man, the most terrible of the beasts. That is why the old religions and the old scriptural language showed so sharp a wisdom when they spoke, not of one’s duty towards humanity, but one’s duty towards one’s neighbour. The duty towards humanity may often take the form of some choice which is personal or even pleasurable. That duty may be a hobby; it may even be a dissipation… But we have to love our neighbour because he is there– a much more alarming reason for a much more serious operation. He is the sample of humanity which is actually given us. Precisely because he may be anybody he is everybody. He is a symbol because he is an accident.” – G.K. Chesterton, http://www.cse.dmu.ac.uk/~mward/gkc/books/heretics/ch14.html