Full Idea
We must distinguish between what is certain and what is necessary; everyone agrees that future contingents are certain, since God foresees them, but it is not thereby admitted that they are necessary.
Clarification
'Contingent' events might not occur
Gist of Idea
Future contingent events are certain, because God foresees them, but that doesn't make them necessary
Source
Gottfried Leibniz (Discourse on Metaphysics [1686], §13)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.23
A Reaction
An interesting point, since there is presumably a difference between God foreseeing that future squares will have four corners, and His foreseeing the next war. It seems to me, though, that 'certainty' is bad enough news for free will, without necessity.