M… was talking about life and how things were going from bad to worse. “I once read,” he said, “that there’s nothing worse for everyone concerned than a reign that’s lasted too long. I’ve also heard that God is eternal. Need we say more?”

[A propos des choses de ce bas monde, qui vont de mal en pis, M… disait: J’ai lu quelque part qu’en politique il n’y avait rien de si malheureux pour les peuples que les règnes trop longs. J’entends dire que Dieu est éternal; tout est dit.]

Nicolas Chamfort (1741-1794) French writer, epigrammist (b. Nicolas-Sébastien Roch)

Products of Perfected Civilization [Produits de la Civilisation Perfectionnée], Part 2 “Characters and Anecdotes [Caractères et Anecdotes],” ch. 3 (1795) [tr. Parmée (2003), ¶ 318]
    (Source)

(Source (French)). Alternate translations:

Speaking of matters here below and how they go from bad to worse, M—— said, “I read somewhere that in politics nothing was so unfortunate for the people as reigns that lasted too long. I hear that God is eternal. There is nothing more to be said.”
[tr. Merwin (1969)]

In politics ... nothing is as unfortunate for the people as reigns which last too long. I hear that God is eternal -- which says it all.
[tr. Dusinberre (1992), frag. 769]