Seneca · On the philosopher's seclusion
Letters 8.9
I shall quote one verse of his, which concerns philosophy, and particularly that phase of it which we were discussing a moment ago, wherein he says that the gifts of Chance are not to be regarded as part of our possessions:
Still alien is whatever you have gained By coveting.
Seneca, Letters to Lucilius 8.9, translated by Richard Mott Gummere