Full Idea
The intelligent cause ought to be infinite in all ways, and absolutely perfect in power, in wisdom, and in goodness, since it relates to all that which is possible. Also, since all is connected together, there is no ground for admitting more than one.
Gist of Idea
The intelligent cause must be unique and all-perfect, to handle all the interconnected possibilities
Source
Gottfried Leibniz (The Theodicy [1710], p.128), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.II
Book Reference
Perkins,Franklin: 'Leibniz: Guide for the Perplexed' [Continuum 2007], p.21
A Reaction
Notice that Leibniz's possible worlds seem to be all connected together, unlike David Lewis's worlds, which are discrete. Personally I suspect that all perfections will lead to contradiction, though Leibniz strongly argues against it.
Related Idea
Idea 19326 God must be intelligible, to select the actual world from the possibilities [Leibniz]