Letters 94.72

Therefore, if our dwelling is situated amid the din of a city, there should be an adviser standing near us. When men praise great incomes, he should praise the person who can be rich with a slender estate and measures his wealth by the use he makes of it. In the face of those who glorify influence and power, he should of his own volition recommend a leisure devoted to study, and a soul which has left the external and found itself.

Seneca, Letters to Lucilius 94.72, translated by Richard Mott Gummere