Letters 27.3

Cast about rather for some good which will abide. But there can be no such good except as the soul discovers it for itself within itself. Virtue alone affords everlasting and peace-giving joy; even if some obstacle arise, it is but like an intervening cloud, which floats beneath the sun but never prevails against it.”

Seneca, Letters to Lucilius 27.3, translated by Richard Mott Gummere