במדבר לד:ה פירוש: רש״י, רשב״ם ורבנו בחיי

והיו תוצאותיו הימה AND ITS GOINGS OUT SHALL BE AT THE SEA i.e. at the western boundary, because the southern border does not extend any more west of there and further on.

והיו תוצאותיו הימה, the whole boundary there forms a southern-westerly wedge, apex.

נחלה מצרים, “to the stream of Egypt.” This means: “to the river dividing Egypt from Palestine,” and not to the river Nile.