The phrase "that you may prolong your days in the land" is repeated throughout the book. The land may be theirs for all time, but because of disobedience their days in the land were not prolonged; they were cast out by the Assyrians, Babylonians, and Romans. If they are also cast out by Hamas and Hezbollah, it will be the consequence of disobedience.4:40 You shall therefore keep His statutes and His commandments which I command you today, that it may go well with you and with your children after you, and that you may prolong your days in the land which the Lord your God is giving you for all time.
There may be a future right to occupy the physical land "when you turn to the Lord your God and obey His voice" (4:30) but that day has not yet come.
In Christ, we receive the promises of Abraham (Gal. 3). But the promise of justification by faith is so much more important than the land, and there's better land elsewhere anyway, as those who have seen it will agree. The earth is the Lord's.