Many people regard the Harry Potter series with a great deal of suspicion. I don't wish to argue the point now (or ever, for that matter), but to lift a major theme from the works for a moment of reflection.
Throughout the six-book series thus far much emphasis is placed by some on being "Pure blood" wizards. In almost every case, those who insist upon purity of blood are at best loathsome and most often outright evil. Rowling isn't writing allegory, but if we look in the world at those who insist upon purity of blood as a mark of rank, we will more often than not encounter ideologies that are antithetical to life.
What brought all of this to mind was a minor passage in Wilfrid McGreal's At the Fountain of Elijah: The Carmelite Tradition, a well-written and brief survey of the history of the Carmelite Order. In the chapter on the contributions of St. John of the Cross and St. Teresa of Avila, McGreal notes:
It is also interesting that both Teresa and John, to use a modern terms, were 'disadvantaged' and were therefore in a special way already poor. Neither Teresa nor John possessed limpieza de sangre--'purity of blood.' They had Jewish forbears, and this ancestry was viewed with suspicion and could be the reason for persecution. By the end of the sixteenth century religious orders in Spain had made limpieza de sangre a condition for admission. Fortunately the Carmelites did not put such legislation into place until 1596.
What a crime against love! Today, many of us can see that this is simply unacceptable for any Christian. It would be difficult to say and believe "You will know they are Christians by their love," under such conditions. And yet, such is the history of humanity--not merely of Christianity. And it is horrifying to think of what we would have lost had this edict been in place some years before.
Prejudice is ugly whenever and however it occurs. We have grown too haughty and proud--we think ourselves beyond it. But prejudice raises its ugly head in every corner and every precinct. Even now, each day, we are tempted to formulate opinions based on appearance, creed, or opinions. Prejudice hates a person for an artifact of that person. Christianity stands in firm opposition--loving the person but showing no mercy to the illicit accidents of the person. Whenever the cry of "Pure blood!" is raised, it is certain the the inevitable end is that blood will be spilled--"pure" and otherwise.