Genesis 10:21

“Unto Shem also, the father of all the children of Eber, etc.] And for the sake of those Shem is particularly said to be the father of, is this genealogy given, and indeed the whole book of Genesis wrote: Eber was the great-grandson of Shem, and is here spoken of by anticipation, and Shem is called not the father of either of his immediate sons, but of the posterity of this man; because the Hebrews sprung from him in his line, among whom the church of God and the true religion were preserved, and from whom the Messiah was to come, as he did: the word Eber, Jarchi interprets, “beyond the river, Euphrates” or “Tigris”, or both, as describing the seat of the posterity of Shem; but as this too…”

“Unto Shem--The historian introduces him with marked distinction as "the father of Eber," the ancestor of the Hebrews.”

“- XXXIII. Shem 21. אבר 'eber, “‘Eber, yonder side; verb: pass, cross.” 22. עילם 'eylām, “‘Elam.” עוּל ‛ûl, “suckle.” עלם ‛ālam, “hide; be mature.” ארפכשׁד 'arpakshad, “Arpakshad.” כשׂד ארף 'arp keśed, “boundary of Kesed, or (von-Bohlen) Arjapakshata, beside Aria.” ארם 'ǎrām, “Aram, high; verb: be high.” 23. עוּץ ‛ûts, “‘Uts; verb: counsel; be firm, solid.” חוּל chûl, “Chul; verb: rub, twist, writhe, be strong, await.” גתר geter, “Gether, bridge?” משׁ meshek, “Mash; related: feel, touch.” 24. שׁלח shelach, “Shelach, missile, shoot.” 25. פלג peleg, “Peleg; noun: brook, canal; verb: divide.” יקטן yāqṭān, “Joctan, small.” 26. אלמודד 'almôdād, “Almodad.” למד lāmad, “learn.” מדד…”

“10:21 Shem, the older brother of Japheth, was the father of the Semitic peoples. The descendants listed represent countries east of Israel (modern Iraq, Iran, and Syria). The narrator lists these locations within Mesopotamia since Abram, the father of Israel, originated from this area (see 11:27-32). • Eber receives special attention because of his connection with Abram (see study note on 10:24).”