Full Idea
We say of a sandal which is not worn that it is in vain; God and nature, however, do nothing in vain.
Clarification
'Nature' is the Greek word 'physis'
Gist of Idea
An unworn sandal is in vain, but nothing in nature is in vain
Source
Aristotle (On the Heavens [c.336 BCE], 271a33)
Book Reference
Aristotle: 'On the Heavens I and II', ed/tr. Leggatt,Stuart [Aris and Phillips 1995], p.61