Letters 116.3

Every emotion at the start is weak. Afterwards, it rouses itself and gains strength by progress; it is more easy to forestall it than to forgo it. Who does not admit that all the emotions flow as it were from a certain natural source? We are endowed by Nature with an interest in our own well-being; but this very interest, when overindulged, becomes a vice. Nature has intermingled pleasure with necessary things—not in order that we should seek pleasure, but in order that the addition of pleasure may make the indispensable means of existence attractive to our eyes. Should it claim rights of its own, it is luxury.

Let us therefore resist these faults when they are demanding entrance, because, as I have said, it is easier to deny them admittance than to make them depart.

Seneca, Letters to Lucilius 116.3, translated by Richard Mott Gummere