In Parshat Lekh Lekha, the Torah broadly defines the land of Israel as stretching from the Nile to the Euphrates (B’reishit 15:18).
But in Parshat Mas’ei, the Torah provides a more detailed definition of Israel’s borders in a much smaller territory between the Mediterranean and the Jordan (Bamidbar 34:1-12).
The request by the tribes of Gad and Reuven for territory east of the Jordan – and Moshe’s reaction – might help clarify this distinction.
I thought that B’reishit 15:18 refers to the river of Egypt (Naḥal Mitzrayim), also known as Wadi al-Arish.
Not the Nile.
Besides, isn’t it counterintuitive that the Sinai is associate with exile and Egypt is associated with bondage, and yet the Nile interpretation would include those places in the Promised Land? Including the eastern part of geographical Egypt, east of the Nile. Are you sure that you’re not misinterpreting the Tanakh?
Regarding the Land of Israel, I thought that the biblical borders are from the Mediterranean to the Jordan + the Golan Heights + Lebanon.