Always verify quotations! – Martin Joseph Routh, quoted in Catholic World: A Monthly Magazine of General Lit

Then your words of abuse today may turn into a universally valid principle of denigration, for words are magical formulae. They leave fingermarks behind on the brain, which in the twinkling of an eye becomes the footprints of history. One ought to watch one’s every word. – Franz Kafka, quoted by Gustav Janouch, Conversations with Kafka

[B]ut in literature, it should be remembered, a thing always becomes his at last who says it best, and thus makes it his own. – James Russell Lowell

…the curious hunter-up of rare quotations… the young and struggling scribbler… – William Francis Henry King, “Introduction,” Classical and Foreign Quotations, 18