Adam Clarke on Exodus 6:14

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 Exo 6:14-26 inclusive, is a sort of parenthesis, and does not belong to the narration; and what follows from Exo 6:28 is a recapitulation of what was spoken in the preceding chapters.