Full Idea
Reason is and ought to be the slave of the passions, and can never pretend to any other office than to serve and obey them.
Gist of Idea
Reason is and ought to be the slave of the passions
Source
David Hume (Treatise of Human Nature [1739], II.III.3)
Book Reference
Hume,David: 'A Treatise of Human Nature', ed/tr. Mossner,Ernest C. [Penguin 1969], p.462