These be the heads - ראשי rashey, the chiefs or captains. The following genealogy was simply intended to show that Moses and Aaron came in a direct line from Abraham, and to ascertain the time of Israel's deliverance. The whole account from Exodus 6:14-26; inclusive, is a sort of parenthesis, and does not belong to the narration; and what follows from Exodus 6:28; is a recapitulation of what was spoken in the preceding chapters.
These be the heads - We have in the following verses, not a complete genealogy, but a summary account of the family of the two brothers. Moses records for the satisfaction of Hebrew readers, to whom genealogical questions were always interesting, the descent and position of the designated leaders of the nation. See Exodus 6:26-27.