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

The borrowing is often honest enough, and comes of magnanimity and stoutness. A great man quotes bravely and will not draw on his invention when his memory serves him with a word as good. – Ralph Waldo Emerson, “Quotation and Originality,” Letters and Social Aims, 1876

There are single thoughts that contain the essence of a whole volume, single sentences that have the beauties of a large work, a simplicity so finished and so perfect that it equals in merit and in excellence a large and glorious composition. – Joseph Joubert (1754–1824), translated from French by George H. Calvert, 1