They are the abridgments of wisdom. – Sumner Ellis, Hints on Preaching: A Cloud of Witnesses, 1879

The man whose book is filled with quotations, may be said to creep along the shore of authors, as if he were afraid to trust himself to the free compass of reasoning. – Quoted unattributed in The Universal Magazine of Knowledge and Pleasure, April 1

That part of a work of one author found in another is not of itself piracy, or sufficient to support an action; a man may adopt part of the work of another; he may so make use of another’s labors for the promotion of science and the benefit of the public. – Lord Ellenborough, quoted in Bouvier’s Law Dictionary by John Bouvier, 8th

Seek not to know who said this or that, but take note of what has been said. – Thomas à Kempis, The Imitation of Christ, translated from Latin