Seneca · On philosophy, the guide of life
Letters 16.5
Whether the truth, Lucilius, lies in one or in all of these views, we must be philosophers; whether Fate binds us down by an inexorable law, or whether God as arbiter of the universe has arranged everything, or whether Chance drives and tosses human affairs without method, philosophy ought to be our defence. She will encourage us to obey God cheerfully, but Fortune defiantly; she will teach us to follow God and endure Chance.
Seneca, Letters to Lucilius 16.5, translated by Richard Mott Gummere