Letters 94.43

Moreover, who can deny that even the most inexperienced are effectively struck by the force of certain precepts? For example, by such brief but weighty saws as: “Nothing in excess,” “The greedy mind is satisfied by no gains,” “You must expect to be treated by others as you yourself have treated them.” We receive a sort if shock when we hear such sayings; no one ever thinks of doubting them or of asking “Why?” So strongly, indeed, does mere truth, unaccompanied by reason, attract us.

Seneca, Letters to Lucilius 94.43, translated by Richard Mott Gummere