Letters 83.19

Think of Alexander of Macedon, who stabbed Clitus, his dearest and most loyal friend, at a banquet; after Alexander understood what he had done, he wished to die, and assuredly he ought to have died.

Drunkenness kindles and discloses every kind of vice, and removes the sense of shame that veils our evil undertakings. For more men abstain from forbidden actions because they are ashamed of sinning than because their inclinations are good.

Seneca, Letters to Lucilius 83.19, translated by Richard Mott Gummere