What are the implications of "ha'Hu Nikra Eretz Refa'im"?
Rashi and Rashbam: It implies that the land of Og Melech ha'Bashan is the land of the Refa'im that Hashem gave to Avraham, but not the lands mentioned earlier in the Parshah, even though also they were called 'Eretz Refa'im'.
Ramban: The Torah is simply saying that they took possession of the entire area specified, which
was all called the land of the Refa'im.
Ramban: As if it had written "asher Hu Nikra Eretz Refa'im" - as we find in Divrei ha'Yamim 1, 26:28 and in Ezra 10:17.
But does not preclude the other areas that were called 'Eretz Refa'im' (Refer to 2:20:2:2).