After all, all he did was string together a lot of old, well-known quotations. – H.L. Mencken, about Shakespeare

Proverbs are in the world of thought what gold coin is in the world of business—great value in small compass, and equally current among all people. Sometimes the proverb may be false, the coin counterfeit, but in both cases the false proves the value of the true. – Attributed to D. March in A Dictionary of Thoughts: A Cyclopedia of Laconic Quot

We prefer to think that the absence of inverted commas guarantees the originality of a thought, whereas it may be merely that the utterer has forgotten its source. – Clifton Fadiman, The American Treasury, 1455-1955, 1955

Nothing ever becomes real till it is experienced—even a Proverb is no proverb to you till your Life has illustrated it. – John Keats, letter to George and Georgiana Keats, February 24, 1819