I once rebuked a friend for misquoting the line about the mills of God, but was chastened to find on looking it up that I had quite the wrong idea about the source: Blake, I had vaguely thought, or 1st Corinthians, or something of that kind. Not at all: the line is from a translation of the Sinngedichte of Friedrich von Logau ("Gottesmuhlen mahlen langsam...."). How about that?
And how many people know the terrifying second line?
Though the mills of God grind slowly, yet they grind exceeding small;
With patience He stands waiting, with exactness grinds He all.
....and if you say it out loud, tum-ti tum-ti tum-ti tum-ti, you can tell that the translator was Longfellow, as in: And the gentle Mudjekeewis/Raven head submissive bowed/Takes her hankie very slowly/Blows her nose exceeding loud.