CVI. — On the Corporeality of Virtue
My tardiness is answering your letter was not due to press of business. Do not listen to that sort of excuse; I am at liberty, and so is anyone else who wishes to be at liberty. No man is at the mercy of affairs. He gets entangled in them of his own accord, and then flatters himself that being busy is a proof of happiness.
Seneca Epistles 93-124, Translation by Richard Gummere. Loeb Classical Library.