DON LOUIS: No, no, birth is nothing where virtue is not. […] Know that a man of noble birth who leads an evil life is a monster in nature; virtue is the prime title of nobility; I care much less for the name a man signs than for the deeds he does; and I should feel more esteem for the son of a porter who was a true man, than for the son of a king who lived as you do.

[Non, non, la naissance n’est rien où la vertu n’est pas. […] Apprenez enfin qu’un gentilhomme qui vit mal est un monstre dans la nature ; que la vertu est le premier titre de noblesse ; que je regarde bien moins au nom qu’on signe, qu’aux actions qu’on fait, et que je ferais plus d’état du fils d’un crocheteur, qui serait honnête homme, que du fils d’un monarque qui vivrait comme vous.]

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

Don Juan [Dom Juan], Act 4, sc. 6 (1665) [tr. Page (1908)]
    (Source)

Don Louis (Don Luis) speaking to his son, Don Juan.

(Source (French)). Other translations:

No, no; Birth is nothing, where there's no Virtue. [...] Know, in short, that a Gentleman who lives ill, is a Monster in nature, that Virtue is the prime Title to Nobility, that I look much less upon the Name we subscribe, than the Actions that we perform, and that I shou'd value more being the Son of a Porter, who was an honest Man, than the Son of a Monarch who liv'd as you do.
[tr. Clitandre (1672)]

No, no! Rank is nothing without virtue. [...] Know, finally, that a nobleman who leads a wicked life is a monster in nature; that virtue is the prime badge of nobility; that I regard much less the name which a man bears than the actions which he commits, and that I should value more highly a porter's son who was an honest man, than a monarch's son who led such a life as yours.
[tr. Van Laun (1876)]

No, no; birth is nothing where virtue is not. [...] Know that a man of noble blood who leads a bad life is a monster in nature, and that virtue is the first title to nobility. I look less to the name that is signed, than to the actions; and I should be more proud of being the son of an honest porter than that of a monarch who lived your life.
[tr. Wall (1879)]

No, no; where virtue is wanting birth does not signify anything. [...] Know, indeed, that a man of noble blood who leads a bad life is an unnatural monster; that virtue is the chief title to nobility; that I regard far less the name which one signs than the actions which one performs; and that I would rather be the son of a porter and honest than the son of a monarch and like you.
[tr. Waller (1904)]

No, no, birth means nothing without virtue. [...] A nobleman who lives by evil is a natural monster. The first title to nobility is rectitude. For me the name a man signs counts for much less than the actions he performs, and I esteem a farm-laborer's honest son more highly than a king's son who lives as you do.
[tr. Bermel (1987)]