De Stoicorum repugnantiis

I first lay this down for an axiom, that there ought to be seen in men’s lives an agreement with their doctrines. For it is not so necessary that the pleader (as Aeschines has it) and the law speak one and the same thing, as that the life of a philosopher be consonant to his speech. For the speech of a philosopher is a law of his own and voluntarily imposed on himself, unless they esteem philosophy to be a game, or an acuteness in disputing invented for the gaining of applause, and not—what it really is—a thing deserving our greatest study.