Joshua 13:15

Inheritance of the tribe of Reuben. This territory was the most southerly of the trans-Jordanic possessions of Israel, and adjoined Moab, which lay only on the other side of the Arnon. Hence, the Reubenites became in after times much intermixed with the Moabites, who in fact eventually acquired much of the land, and several, if not all, of the cities here named as belonging to Reuben. This acquisition was probably assisted by the fact that the territory north of Arnon had formerly belonged to the Moabites, from whom it was wrested by the Amorites (see Numbers 21:27, etc. notes). It is not likely that the Amorite conquerors had completely extirpated the Moabite inhabitants. Hence, in the days when the Reubenites became engrossed in their pastoral pursuits, and probably not very long after the days of Joshua, the Moabites easily encroached on their inheritance, and in the end probably reoccupied nearly the whole of the ancient kingdom of Sihon (Compare Deuteronomy 33:6 note).

13:15 According to their families - Dividing the inheritance into as many parts as they had families; but this is only spoken of the greater families; for the lesser distributions to the several small families was done by inferior officers, according to the rules which Moses gave them.