יחזקאל, פרק מ״ח, פסוק כ״ח

The southern frontier of the Land of Israel serves as a definitive boundary, marking the absolute edge of the nation's inheritance. This southernmost line perfectly overlaps with the southern border of the tribe of Gad's territory. The commentators agree that the edge of Gad's land does not merely define the tribe's personal limits, but acts as the official boundary for the entire country, situated entirely along the southern side [מצודת ציון].

The exact route of this border stretches across the land, beginning at the eastern corner in a place called Tamar. This location is identified by some as the city of Jericho, famously known as the city of dates [רש״י]. From this eastern starting point, the boundary line travels westward toward the waters of Merivat Kadesh. It then meets a river, which is widely understood to be the River of Egypt [רש״י, מצודת דוד, ביאור שטיינזלץ]. This river continues to flow westward until it empties directly into the Mediterranean Sea. The exact point where the water meets the sea establishes the final southwestern corner of the border, completing the outline of the land [רש״י, מצודת ציון].