Komentarz do Powtórzonego Prawa 3:12

ואת הארץ הזאת AND THIS LAND mentioned above (v. 8), "from the brook of Arnon to Mount Hermon", ירשנו בעת ההוא WE POSSESSED AT THAT TIME.

ואת הארץ הזאת ירשנו בעת ההיא, “and we inherited this land at that time.” Rashi says that the words ואת הארץ הזאת refer to the land mentioned just previously. The words מערורר אשר על נחל ארנון, are not connected to what has been described previously, but introduce a new section, seeing that the people of Israel inherited more territory, lands inherited by the tribes of Reuven and Gad mentioned at the end of the verse. This is clear from the fact that Mount Hermon is situated far to the north of the river Arnon. Nachmanides writes that in his view the words הארץ הזאת אשר ירשנו בעת ההיא וגגו' were all regions given to the tribe of Reuven.

“Mentioned above, etc. I.e., it is not referring to the land mentioned afterwards, “From Aro’er which is on Wadi Arnon.” For the land they inherited at that time extended from Wadi Arnon to Mount Chermon, and not only from Aro’er until half of Mount Gilod. Rather, the verse means: “The land mentioned above that we took from the two kings, which extended from Wadi Arnon until Mount Chermon, we inherited it and fortified it.” Afterwards starts a new account: “From Aro’er which is on Wadi Arnon ... I gave to the Reuvenites and the Gaddites, and I gave the rest to half the tribe of Menashe, etc.”