When virtue is banished, ambition invades the hearts of those who are disposed to receive it, and avarice possesses the whole community.

[Lorsque cette vertu cesse, l’ambition entre dans les cœurs qui peuvent la recevoir, & l’avarice entre dans tous.]

Charles-Lewis de Secondat, Baron de Montesquieu (1689-1755) French political philosopher

Spirit of Laws [The Spirit of the Laws; De l’esprit des lois], Book 3, ch. 3 (3.3) (1748) [tr. Nugent (1750)]
    (Source)

Speaking of republics. See notes here on Montesquieu's meaning of "virtue": political virtue of love of country and of equality.

(Source (French)). Other translations:

When that virtue ceases, ambition enters those hearts that can admit it, and avarice enters them all.
[tr. Cohler/Miller/Stone (1989)]

When that virtue ceases, ambition enters the hearts that can receive it, and avarice enters them all.
[tr. Stewart (2018)]