Letters 114.23

If but the king be safe, your swarm will live Harmonious; if he die, the bees revolt.

The soul is our king. If it be safe, the other functions remain on duty and serve with obedience; but the slightest lack of equilibrium in the soul causes them to waver along with it. And when the soul has yielded to pleasure, its functions and actions grow weak, and any undertaking comes from a nerveless and unsteady source.

Seneca, Letters to Lucilius 114.23, translated by Richard Mott Gummere