Seneca · On the good which abides
Letters 27.9
But let me pay off my debt and say farewell: “Real wealth is poverty adjusted to the law of Nature.” Epicurus has this saying in various ways and contexts; but it can never be repeated too often, since it can never be learned too well. For some persons the remedy should be merely prescribed; in the case of others, it should be forced down their throats. Farewell.
Seneca, Letters to Lucilius 27.9, translated by Richard Mott Gummere