Do not shun this maxim because it is common-place. On the contrary, take the closest heed of what observant men, who would probably like to show originality, are yet constrained to repeat. Therein lies the marrow of the wisdom of the world. – Arthur Helps, “Chapter IV,” Companions of My Solitude, 1851

The mind will quote whether the tongue does or not. – Attributed to Emerson in Edge-Tools of Speech by Maturin M. Ballou, 1886

But further, in order to embellish it with flowers of language and gems of thought, it is not necessary for this ornamentation to be spread evenly over the entire speech, but it must be so distributed that there may be brilliant jewels placed at various points as a sort of decoration. – Cicero, De oratore

QUOTATION, n. The act of repeating erroneously the words of another. The words erroneously repeated. – Ambrose Bierce, The Devil’s Dictionary