Every book is a quotation; and every house is a quotation out of all forests and mines and stone quarries; and every man is a quotation from all his ancestors. – Ralph Waldo Emerson, “Plato; Or, The Philosopher”

In these circumstances I think we must take the bull by the horns… and, making due allowances, quote whenever we feel that the allusion is interesting or helpful or amusing. – Clifton Fadiman, c.1955

We are as much informed of a writer’s genius by what he selects as by what he originates. – Ralph Waldo Emerson, “Quotation and Originality,” Letters and Social Aims, 1876