[From “Is Lebanon part of Israel’s promised territory?”]

Archived here

The Torah verses convey profound messages that we can insightfully extract for our daily lives. Rabbi Shay Tahan, the Rosh Kollel of Shaarei Ezra in Brooklyn, NY, graciously opens the gates to understand them

The recent conflict in Lebanon raises the age-old question regarding the northern borders of biblical Eretz Yisrael. Where exactly did Hashem define the boundaries, and are we obligated to conquer those areas?[…]
At the blessing at the end of Parshat Ekev, Hashem tells us that we are granted every land we will conquer within the borders mentioned. In the north, the Torah states: "Every place where the sole of your foot will tread shall be yours—from the wilderness and the Lebanon, from the river—the Euphrates River—until the western sea shall be your boundary." This promise from the Creator clearly places the land of Lebanon within the Promised Land of Israel[…]
Expanding Israel’s borders would mean extending the requirement to observe these mitzvot in the newly included territories[…]
Inhabitants and Settlement: According to some opinions, living in the biblical boundaries of Eretz Yisrael may be considered a mitzvah. Expanding Israel’s borders could extend the obligation for Jews to settle and inhabit those areas[…]
War and Conquest: The concept of milchemet mitzvah (a commanded war) includes conquering certain territories that were promised in the Torah. If new land is identified as part of the biblical borders, there may be halachic discussions about the obligation to conquer and settle it[…]
If one looks at a map, they will be astounded by how far north this river extends and how vast the Land of Israel truly is. While we may not be able to reclaim all of it in our time, Hashem will surely return it to us soon