Letters 92.13

And you may assume that what I have said about dress applies also to the body. For nature has surrounded our soul with the body as with a sort of garment; the body is its cloak. But who has ever reckoned the value of clothes by the wardrobe which contained them? The scabbard does not make the sword good or bad. Therefore, with regard to the body I shall return the same answer to you,—that, if I have the choice, I shall choose health and strength, but that the good involved will be my judgment regarding these things, and not the things themselves.

Seneca, Letters to Lucilius 92.13, translated by Richard Mott Gummere