MERCURY: An easygoing vice, I hold, is better than an angry virtue.

MERCURE: [J’aime mieux un vice commode,
Qu’une fatigante vertu.]

Molière (1622-1673) French playwright, actor [stage name for Jean-Baptiste Poquelin]

Amphitryon, Act 1, sc. 4, ll. 681-682 (1668) [tr. Wilbur (2010)]
    (Source)

Suggesting to his wife, Cleanthis, that he'd rather she take a lover than keep pestering him, at his age, to be one.

(Source (French)). Other translations:

I would sooner have a convenient vice, than a worrying virtue.
[tr. Van Laun (1876)]

I prefer a convenient vice to an irksome virtue.
[tr. Wall (1879)]

I prefer an accommodating vice to an obstinate virtue.
[ed. Ballou (1886)]

I prefer a convenient vice, to a fatiguing virtue.
[tr. Waller (1903)]