Gen 10:21

10:21 father of all. Or, “ancestor of all” (cf. 5:3–32 note). The Hebrew term for “father” was used for more remote ancestors (28:13). Shem was Eber’s great-great-grandfather (10:24; 11:10–14).

Eber. The word for “Hebrew” probably comes from this name (cf. 14:13 note). He is the heir of God’s blessing on Shem, just as Canaan, son of Ham, was the target of Noah’s curse. Some scholars identify Eber with Ebrum, an ancient king of Ebla (c. 2300 b.c.).

brother of Japheth. Because of the translation difficulty, it is uncertain whether Shem or Japheth was the oldest. Ham was likely the youngest (9:24). Assuming the text note reading, Moses here stresses the firstborn status of Shem, despite the fact that his genealogy is presented last.