Full Idea
The idea of God, that is, the idea of a supremely perfect being, is one discovered to be no less within me than the idea of any figure or number.
Gist of Idea
The idea of a supremely perfect being is within me, like the basic concepts of mathematics
Source
René Descartes (Meditations [1641], §5.65)
Book Reference
Descartes,René: 'Discourse on Method/The Meditations', ed/tr. Sutcliffe,F.E. [Penguin 1968], p.144