German is widely known as the language of the Dichter und Denker, writers and thinkers. One of the greatest is Johann Wolfgang von Goethe (1749-1832). His drama Faust I (1808) is considered his greatest work and a national treasure, as well as the source of many quotations still present in everyday German.
The phrase des Pudels Kern, lit. the core of the poodle, is often used for expressing a deeper meaning. Named after the character Gretchen in Faust, die Gretchenfrage, lit. the Gretchen question, aims at your heart and soul, often triggering a confession or a difficult decision.
From a more recent source by another famous German writer, Bertolt Brecht (1898-1956), comes the ultimate insight into human nature:
Erst kommt das Fressen, dann kommt die Moral.
Food comes first, then morals.
Die Dreigroschenoper, The Threepenny Opera, 1928