All well-known quotations that are attributable to an individual or to a text require citations. You should quote a famous saying as it appears in a primary or secondary source and then cite that source. While it is acceptable to cite a famous saying from a website or a book that lists famous quotations, quoting from the original source provides readers with more context and could strengthen the argument you are making. The following two sentences provide examples:

As Alexander Pope said, “A little Learning is a dang’rous Thing” (line 215).

As Alexander Pope said, “A little learning is a dangerous thing” (qtd. in Bartlett).

Works Cited

Bartlett, John. Familiar Quotations: A Collection of Passages, Phrases, and Proverbs Traced to Their Sources in Ancient and Modern Literature. Little, Brown, 1919. Bartleby, 2000, www.bartleby.com/100/230.99.html.

Pope, Alexander. An Essay on Criticism. The Poems of Alexander Pope, edited by John Butt, Yale UP, 1963, pp. 144–68.

However, common figures of speech do not require a citation, as in the following:

Even though the novel appeared to be highly original at first, it turns out that “there’s nothing new under the sun.”

The phrase “there is no new thing under the sun” comes from Ecclesiastes, but it has become proverbial and so does not require a citation.