Letters 66.7

There you have its outward appearance, if it should ever come under a single view and show itself once in all its completeness. But there are many aspects of it. They unfold themselves according as life varies and as actions differ; but virtue itself does not become less or greater. For the Supreme Good cannot diminish, nor may virtue retrograde; rather is it transformed, now into one quality and now into another, shaping itself according to the part which it is to play.

Seneca, Letters to Lucilius 66.7, translated by Richard Mott Gummere