John Gill Bible Commentary

And the sons of Levi, Gershon, Kohath, and Merari. From these sprung the priests and Levites, see Num 3:1. . Genesis 46:12 gen 46:12 gen 46:12 gen 46:12And the sons of Judah, Er, and Onan, and Shelah, and Pharez, and Zarah,.... Five of them: but Er and Onan died in the land of Canaan; and so did not go with Jacob into Egypt; and which is observed that they might not be reckoned among them, though it was proper to take notice of them in the genealogy: and the sons of Pharez were Hezron and Hamul; some think that these could not be born in Canaan, but in Egypt; and that they are mentioned among those that went down to Egypt, because they went there in the loins of their father, and to supply the places of Er and Onan, who died before, and have the honour to be here named, because they might be the first of Jacob's great grandchildren born there; though others suppose that Pharez was at this time fourteen years of age, and instances are given of some, who before that age have been fathers of children; the difficulty is not easily solved: the Targum of Jonathan expressly says,"Shelah and Zarah did not beget children in Canaan, but there were two sons of Pharez who went down into Egypt, Hezron and Hamul.''