Full Idea
It is impossible to imagine that anything is thought of in the divine intellect as good or true, or worthy of belief or action or omission, prior to the decision of the divine will to make it so.
Gist of Idea
Ideas in God's mind only have value if he makes it so
Source
René Descartes (Reply to Sixth Objections [1641], 432)
Book Reference
Descartes,René: 'Meditations on First Philosophy etc.', ed/tr. Cottingham,John [CUP 1986], p.93