Quotations about:
    knave

ALCESTE: His social polish can’t conceal his nature;
One sees at once that he’s a treacherous creature;
No one could possibly be taken in
By those soft speeches and that sugary grin.
The whole world knows the shady means by which
The low-brow’s grown so powerful and rich,
And risen to a rank so bright and high
That virtue can but blush, and merit sigh.

 
[Au travers de son masque on voit à plein le traître;
Partout il est connu pour tout ce qu’il peut être ;
Et ses roulements d’yeux, et son ton radouci
N’imposent qu’à des gens qui ne sont point d’ici.
On sait que ce pied plat, digne qu’on le confonde,
Par de sales emplois s’est poussé dans le monde,
Et que, par eux son sort de splendeur revêtu
Fait gronder le mérite et rougir la vertu.]

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

Le Misanthrope, Act 1, sc. 1 (1666) [tr. Wilbur (1954)]
    (Source)

(Source (French)). Alternate translations:

You may plainly perceive the traitor through his mask; he is well known everywhere in his true colours; his rolling eyes and his honeyed tones impose only on those who do not know him. People are aware that this low-bred fellow, who deserves to be pilloried, has, by the dirtiest jobs, made his way in the world; and that the splendid position he has acquired makes merit repine and virtue blush.
[tr. Van Laun (1878)]

The treacherous rascal is plainly seen through his mask, he is everywhere known for what he is; his rolling eyes and soft tones impose only upon strangers. People know that this wretched fellow, who ought to be hanged, has pushed his way in the world by dirty jobs, and that the splendid condition he finds himself in through them makes merit grumble and virtue blush.
[tr. Mathew (1890)]

Behind his mask the knave is seen, wherever he is known, for what he is; the rolling of his eye, his bated voice, impose on none but those who do not live here. All others know that the sneaking fellow, fit only to be shunned, has by the foulest actions foisted himself upon society, where his career, by their connivance clothed in splendor, makes merit groan and virtue blush.
[tr. Wormeley (1894)]

You can clearly see the traitor through his mask. He is known everywhere for what he is: his rolling eyes and his honeyed tones only impose on those people who do not know him. They know that this low-bred cur, who deserves to be exposed, has, by the dirtiest means, pushed himself on in the world; and the splendid position he has acquired by these means makes merit repine and virtue blush.
[tr. Waller (1903)]

The traitor's face shows plainly through his mask,
And everywhere he's known for what he is;
His up-turned eyes, his honeyed canting voice,
Impose on none but strangers. All men know
That this confounded, low-bred, sneaking scamp
Has made his way by doing dirty jobs,
And that the splendid fortune these have brought him
Turns merit bitter and makes virtue blush.
[tr. Page (1913)]

Behind his mask the scoundrel's visible.
Here everybody knows his character;
And his protesting eyes, his honeyed tongue,
Impose on no one but a casual stranger.
And that contemptible boor notoriously
Has made his way in the world by dirty means,
So that his present splendid situation
Makes merit grumble and makes virtue blush.
[tr. Bishop (1957)]

Right through his mask men see the traitor's face,
And everywhere give him his proper place;
His wheedling eyes, his soft and cozening tone,
Fool only those to whom he is not known.
That this knave rose, where he deserved to fall,
By shameful methods, is well known to all,
And that his state, which thanks to these is lush,
Makes merit murmur and makes virtue blush.
[tr. Frame (1967)]