They insist: it's right and proper that dripping heads should be displayed above the city gates, and we take in their explanations, how without the heads everything would be much worse, how the heads brought it on themselves by being a sort of people we would never be: and we nod and learn how to cut off heads ourselves.
But comes a time when we pause, and eye the saw dubiously, and dare to think that it might be nice, to come home of an evening and walk under a clean gates that smelled only of sunwarmed stone.
From that moment, we become dangerous: we are outlaws in our hearts, and we no longer saw through the cordage of our batches of necks with the proper zeal. By that time, of course, we are worn and tired, and weighed down with the accumulation of our half-understood sin. There's not much to fear from us. But we still make them uneasy: they still look at us sidelong and suspiciously.
It's lucky for them, lucky that we don't live very long, lucky that we get so tired.