Full Idea
It would have been impossible for the dissimilar and incompatible sources to have been made into an orderly universe unless harmony had been present in some form or other.
Gist of Idea
Harmony must pre-exist the cosmos, to bring the dissimilar sources together
Source
Philolaus (On the Cosmos (lost) [c.435 BCE], B06), quoted by John Stobaeus - Anthology 1.21.7d
Book Reference
'The First Philosophers', ed/tr. Waterfield,Robin [OUP 2000], p.111