Sons of Israel — This is added emphatically, because they were treated as if they had been the immediate sons of Jacob. Not reckoned — This is the second reason, which sheweth both why Reuben's genealogy was not first mentioned; and if another tribe was to be ranked before it, why that was Judah, and not Joseph, because the order of their genealogy was not to be ruled by the birthright, but by an higher privilege, which was given to Judah.
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.