R. Yoshiyah says: What is the intent of (Ibid.) "which He swore to your forefathers to give to you": From (Devarim 26:2) "then you shall take of all the fruits of the earth," I might think that all of the land is intended; you, therefore, reason thus: It is written here (Exodus) "swearing," and there (Devarim, Ibid. 3) "swearing." Just as here, the land of five nations (is intended); there, too, the land of five nations.
Rabbi Yoshiyah Limits the First Fruits Offering to Five Nations
Mekhilta Tractate Pischa 17:2