The truest sayings are paradoxical. – Laozi, as quoted in The Wisdom of the East: The Sayings of Lao Tzŭ, transla

A learned historian declared to me of a contemporary, that the latter had appropriated his researches; he might, indeed, and he had a right to refer to the same originals; but if his predecessor had opened the sources for him, gratitude is not a silent virtue. – Isaac D’Israeli, “Quotation,” A Second Series of Curiosities of Literature

Many moons ago dictionaries of quotations may have been less needed than they are today. In those good/bad old days, people walked around with entire poems and all the Shakespearean soliloquies in their heads…. – Joseph Epstein, Foreword to Fred R. Shapiro’s Yale Book of Quotations, 200

Apothegms to thinking minds are the seeds from which spring vast fields of new thought, that may be further cultivated, beautified, and enlarged. – Ramsay, as quoted in A Dictionary of Thoughts: A Cyclopedia of Laconic Quotation