Full Idea
In all of nature efficient causes correspond to final causes, because everything proceeds from a cause which is not only powerful, but wise; and with the rule of power through efficient causes, there is involved the rule of wisdom through final causes.
Gist of Idea
Power rules in efficient causes, but wisdom rules in connecting them to final causes
Source
Gottfried Leibniz (Metaphysical conseqs of principle of reason [1712], §5)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.174
A Reaction
Nowadays this carrot-and-stick view of causation is unfashionable, but I won't rule it out. The deepest 'why?' we can ask won't just go away. This unity by a divine mind strikes me as too simple, but Leibniz is right to try to unify Aristotelian causes.