We don't understand the exact borders just from the biblical text. It is clear that the border touches the Euphrates in the north east and the "river of Egypt" in the west, and in the north if I recall should reach the Taurus mountains in what is now Turkey. The text however doesn't say that God gave the Israelites the lands of the some of the surrounding neighbors- the Egyptians, the Assyrians, the Babylonians, Aram, Kedar, Amon, Moab, Midyan. So I think we can learn from that that the promise land doesn't include much of Egypt and cannot include more then half of Syria, not much if anything at all of Iraq and Arabia.