Jerome

Arphaxad begot Shelah, and Shelah begot Eber. From Eber were born two sons: one was named Peleg, because in his days the earth was divided, and his brother's name was Joktan. Eber, from whom the Hebrews are descended, gave his son Peleg the name which means 'division', because in his days the languages were divided in Babylon.

Hebrew Questions on Genesis ↗

Bede

But indeed Arphaxad begat Salah, from whom Heber was born. From this Heber both Abraham and the people born from him, as we have mentioned before, are surnamed Hebrew.

Commentary on Genesis (Hexaemeron) ↗