The adventitious beauty of poetry may be felt in the greater delight which a verse gives in happy quotation than in the poem. – Ralph Waldo Emerson, “Art”

I doubt whether Cromwell or Milton could have rivaled [William Lloyd] Garrison in this field of quotation; and the power of quotation is as dreadful a weapon as any which the human intellect can forge. – John Jay Chapman

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