Full Idea
God alone (or the Necessary Being) has the privilege that He must exist if He is possible.
Gist of Idea
God alone (the Necessary Being) has the privilege that He must exist if He is possible
Source
Gottfried Leibniz (Monadology [1716], §45)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.186