His birthright] This was a portion of the inheritance, twice as great as that given to each of the other sons. The two children of Joseph together received the share which, in right of birth, should have been Reuben's, each being placed on a level with their uncles, the sons of Jacob: cp. Genesis 48:5. And the genealogy] Joseph, though receiving Reuben's birthright, is not given precedence of him in the table of descent; and so Reuben's sons are enumerated before Joseph's.
Related Commentaries of 1 Chronicles 5:1
1 Chronicles 5:1
1 Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, forasmuch as he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.