2 Samuel 24:5

Aroer . There is some uncertainty as to the Aroer here meant. There is first a city of that name in the tribe of Gad facing Rabbah ( Joshua 13:25 ), and this is apparently the city meant; for it is said that "Joab and his men pitched in Aroer, on the south side of the city situated in the middle of the valley of Gad, and unto Jazer." Now, Jazer is also in Gad, about seven miles west of Rabbah, and as Rabbah is on the extreme east of the Israelite territory towards Ammon, it would be a very convenient spot from which to commence the numbering, But there is another Aroer on the Arnon, to the south of Reuben, and many commentators think that this Aroer must be meant, as otherwise the tribe of Reuben would seem to have been omitted. But this Aroer is regularly called "Aroer on the brink of the valley of Arnon" ( Deuteronomy 2:36 ; Deuteronomy 4:48 ; Joshua 12:2 ; Joshua 13:9 , Joshua 13:16 ); or simply Aroer "in the valley of Arnon" ( Deuteronomy 3:12 ; 2 Kings 10:33 ); and cannot possibly be "the city in the midst of the valley of Gad," nor can this Aroer be "toward Jazer." Really the difficulty is made by commentators whose idea of the method of the census is superficial. Joab, in commencing it, formed an encampment in the open country on the right-hand side, that is, on the south of Aroer in the tribe of Gad, as being central, with Reuben on the south, and Manasseh on the north. It was "toward Jazer," that is, it was on the Jazer side of Aroer, and not on the side opposite Rabbah. We, with our simpler way of describing the points of the compass, would merely say that Joab's camp was in the open pasture land southwest of Aroer. Joab probably selected this spot because, though on the eastern border, it was yet not too far from Jerusalem, was central, and because a brook from Jazer flowing eastward for some distance, and thence to the north past Rabbah, would supply his people with water; and from this camp he would direct the proceedings of those who were to take the census. And as probably there would be considerable opposition—for the people would see in an act which for four centuries had been in desuetude threats of heavier taxation, of heavier forced labour, and of longer service with the army—Joab would require the presence of a body of troops sufficiently powerful to overawe malcontents. And these would be of no use at Aroer on the Arnon, in the distant south, but must lie eneamped in some central position, whence detachments could rapidly be moved to any place where there was danger of resistance.