Full Idea
The Forms could not be changeless if they were in changing things.
Gist of Idea
The Forms cannot be changeless if they are in changing things
Source
comment on Plato (works [c.375 BCE]) by Aristotle - Metaphysics 998a
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.64