Full Idea
To ask why God did not make everything a year sooner would be reasonable if time were something apart from temporal things, but time is just the succession of things, which remains the same if the universe is created a year sooner.
Gist of Idea
If everything in the universe happened a year earlier, there would be no discernible difference
Source
Gottfried Leibniz (Letters to Samuel Clarke [1716], 3.6)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.212