Jerome : (Verse 21.) And they dug another well, and they quarreled over it. And he called its name Enmity. Concerning enmity, because Aquila and Symmachus translated it as τὴν ἀντικειμένην, and ἐναντίωσιν, which means opposing and contrary, in Hebrew it is Satana (). From which we understand Satana to be interpreted as the opposite. — Hebrew Questions on Genesis