Or HaChaim on Deuteronomy 2:20/אור החיים על דברים ב׳:כ׳

1 ארץ רפאים תחשב אף היא, it is also considered the land of the Rephaim, etc. Rashi says that the reason this land was called the land of the Rephaim was that the Rephaim used to live there at one time; however, this is not the land of the Rephaim G'd had promised to Abraham at the time. I cannot see what forces Rashi to arrive at this conclusion. Where did G'd ever say that these Rephaim were not included in the ones whose land G'd promised to Abraham? On the contrary, whenever Rephaim are mentioned it includes all the people known as Rephaim. I have seen that Rashi supports his theory by saying that his source is the wording of verse ההוא יקרא ארץ רפאים (Deut.3,13). The fact that the Torah stresses there "this is the land called the land of the Rephaim," suggests that only that part of the Bashan was the land G'd had promised to Abraham under the heading of "the land of the Rephaim." The extra word ההוא means that any other land in which the Rephaim lived at different times was not considered as "their land" (compare Rashi in Chulin 60). I am not persuaded by this proof. Why do we have to assume that the word ההוא in Deut 3,13 is meant to exclude other lands occupied by the people known as the Rephaim? Maybe the word is only meant to exclude the district called Argov seeing it is not called "land of the Rephaim?" Logic would dictate that the word ההוא is meant to indicate precisely what the Torah refers to, not something the Torah wants to exclude. After the Torah had told us that the Rephaim used to live in the land occcupied by the Bney Ammon and the Moabites (the descendants of Lot) at that time, the Torah mentions that these lands were really included in what G'd had promised to Abraham at the time. Furthermore, the word ההוא was not intended to restrict except to tell us that at the time Moses spoke these lands were no longer popularly known as the lands of the Rephaim but as the lands of Sichon and Og rather than as the lands of Bney Ammon and Moav. In fact, even at the time when G'd made the promise to Abraham these cities were not known as lands of the Rephaim as G'd had temporarily designated these cities as the inheritance of the descendants of Lot. Rashi (2,5) himself explains that Abraham who had been promised these lands by G'd, turned them over to Lot (temporarily) who went to Egypt with him becaus he did not reveal the secret of the husband-wife relationship between Abraham and Sarah.

2When we keep these points in mind we can understand why the Torah writes יקרא when speaking of the lands of Sichon and Og, whereas when speaking of the lands of the Rephaim the Torah wrote יחשב. Seeing the whole Jewish people remembered that Sichon and Og had lived in those lands the expression יקרא, "is called" (3,13) was quite appropriate. On the other hand, when the Torah speaks of lands whom no one remembered as having been populated by the Rephaim of old, the term תחשב "was considered" (2,19), is more appropriate. I am convinced that whenever the Torah mentions that a certain piece of land was called "the land of the Rephaim," the intention is to tell us that this piece of land was included in what G'd promised to Abraham at the time he mentioned the Rephaim. According to the words of the Sifri which I have quoted in Mattot that the lands of Sichon and Og claimed by the tribes of Reuven and Gad were not the lands which had been promised to Abraham by G'd at the time of the covenant between the pieces, it makes sense that the Torah wrote in Deut. 3.13 ההוא יקרא ארץ רפאים, "that is the land known as the land of the Rephaim." The Torah means to say: "this is what truly deserves to be called the lands of the Rephaim, and not some other lands such as the one of Sichon and Og which has popularly been known as the land of the Rephaim." Please read what else I have to say on the subject in connection with 3,13.