And what is shameful if those who do it don’t think it so?

[τί δ’ αἰσχρὸν ἢν μὴ τοῖσι χρωμένοις δοκῇ]

Euripides (485?-406? BC) Greek tragic dramatist

Æolus [Αἴολος], frag. 19 (TGF) [tr. Aleator (2012)]
    (Source)

This bit of moral relativism (likely coming from Macareus, the son of Aeolus, who committed incest with his sister, Canace) continues to provoke commentary, thus varied translations. Aristophanes includes a reference to this line in his The Frogs.

Nauck frag. 19, Barnes frag. 5, Musgrave frag. 1. (Source (Greek)). Alternate translations:

But what is base, if it appear not base
To those who practice what their soul approves?
[tr. Wodhull (1809)]

What is shameful, if it does not seem to be so to those who do it?
[Source]

What's wrong if they who do it think not so?
[Source (1902)]

Why shameful, if it does not seem so to those who practice it?
[Source (2018)]