במדבר, פרק ל״ד, פסוק ה׳

The careful mapping of the Land of Israel's southern border eventually reaches its final destination, curving toward the western edge. As the boundary line stretches westward, it meets a specific waterway known as the Brook of Egypt. The exact geographical identity of this stream is a matter of careful discussion. The primary approach among commentators is that this brook is absolutely not the Nile River [שד״ל, רבנו בחיי, אבן עזרא]. Instead, the accepted tradition identifies this location as Wadi el-Arish [שטיינזלץ].

In contrast to this view, [תרגום יונתן] surprisingly identifies the brook directly with the Nile. To resolve this unusual identification, it is explained that the border does not reach the main body of the river itself, but rather meets one of the smaller branches extending outward from it [העמק דבר].

After following this waterway, the border's path comes to a complete stop at the Mediterranean Sea [שטיינזלץ]. Reaching the sea establishes the exact southwestern corner of the Land [רשב״ם]. This final meeting point acts as the ultimate western limit, ensuring that the southern border extends no further from this spot [רש״י].