Political virtue is a renunciation of oneself, which is always a very painful thing. One can define this virtue as love of the laws and the homeland. This love, requiring a continuous preference of the public interest over one’s own, produces all the individual virtues; they are only that preference.

[La vertu politique est un renoncement à soi-même, qui est toujours une chose très-pénible. On peut définir cette vertu, l’amour des loix & de la patrie. Cet amour, demandant une préférence continuelle de l’intérêt public au sien propre, donne toutes les vertus particulieres: elles ne sont que cette préférence.]

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 4, ch. 5 (4.5) (1748) [tr. Cohler/Miller/Stone (1989)]
    (Source)

(Source (French)). Other translations:

Virtue is a self-renunciation which is always arduous and painful. This virtue may be defined, the love of the laws and of our country. As this love requires a constant preference of public to private interest, it is the source of all the particular virtues; for they are nothing more than this very preference itself.
[tr. Nugent (1750)]

Virtue is a self-renunciation, which is very arduous and painful. This virtue may be defined as the love of the laws and of our country. As such love requires a constant preference of public to private interest, it is the source of all private virtues [....]
[E.g. (1904)]

Virtue is self-renunciation, which is always a very hard thing. This virtue may be defined as love of the laws and of the homeland. As this love requires a continual preference for the public interest over one’s own, it confers all the separate virtues: they are nothing more than this preference.
[tr. Stewart (2018)]