Unto Shem also, the father of all the children of Eber, the brother of Japheth the elder, even to him were children born. Shem is here called the father of all the children of Eber, the Hebrews in the wider sense of the word, because Eber, through his sons Peleg and Joktan, was the progenitor of two distinct series of peoples, the Joktanites of Arabia and the Abrahamites, afterward the children of Israel.
Related Commentaries of Genesis 10:21
Genesis 10:21
21 Unto Shem also, the father of all the children of Eber, the brother of Japheth the elder, even to him were children born.