The Chinese idiom "一言以蔽之" is formed from a direct quotation in the classical text "The Analects of Confucius", where Confucius states "诗三百，一言以蔽之，曰：思无邪" to mean summarizing the Book of Songs in one phrase. Literally, the components are: "一言" (one word/sentence), "以" (with), "蔽" (to cover/summarize), and "之" (it/them), combining to express the concept of encapsulating something succinctly in a single statement.