Full Idea
There is a difference between truths whose necessity is brute and geometric and those truths which have their source in fitness and final causes.
Gist of Idea
Some necessary truths are brute, and others derive from final causes
Source
Gottfried Leibniz (Letters to Remond de Montmort [1715], 1715.06.22/G III 645), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 6
Book Reference
Garber,Daniel: 'Leibniz: Body, Substance, Monad' [OUP 2009], p.236
A Reaction
The second one is a necessity deriving from God's wisdom. Strictly it could have been otherwise, unlike 'geometrical' necessity, which is utterly fixed.