Joshua
Joshua 13:21ESV·traditional attribution

that is, all the cities of the tableland, and all the kingdom of Sihon king of the Amorites, who reigned in Heshbon, whom Moses defeated with the leaders of Midian, Evi and Rekem and Zur and Hur and Reba, the princes of Sihon, who lived in the land.

Matthew Henry Presbyterian @wholebiblehenry

Here we have, I. Orders given to Joshua to assign to each tribe its portion of this land, including that which was yet unsubdued, which must be brought into the lot, in a believing confidence that it should be conquered when Israel was multiplied so as to have occasion for it (Jos 13:7): Now divide this land. Joshua thought all must be conquered before any must be divided.

Commenting on Joshua 13:7-33

John Gill Reformed Baptist @doctorgill

Balaam also, the son of Beor the soothsayer, did the children of Israel slay with the sword,.... At the same time that the princes of Midian were slain, and which is also observed; see Gill on Num 31:8. Kimchi supposes that he returned to Midian, on hearing that the counsel he gave to them, to ensnare Israel with their daughters, had taken effect, in order...

Adam Clarke Methodist @methodicalclarke

The princes of Midian - See the history of this war, Num 31:1, etc.; and from that place this and the following verse seem to be borrowed, for the introduction of the death of Balaam here seems quite irrelevant.