Jerome of Stridon
It will commence from the wilderness of Sin, adjacent to Edom, with the sea marking the eastern limit. In essence, this indicates that the boundary extends from the wilderness of Sin, situated near Edom, to the Red Sea.
The south side shall begin from the wilderness of Sin, which is by Edom: and shall have the most salt sea for its furthest limits eastward:
וְהָיָ֨ה לָכֶ֧ם פְּאַת־נֶ֛גֶב מִמִּדְבַּר־צִ֖ן עַל־יְדֵ֣י אֱד֑וֹם וְהָיָ֤ה לָכֶם֙ גְּב֣וּל נֶ֔גֶב מִקְצֵ֥ה יָם־הַמֶּ֖לַח קֵֽדְמָה׃
One Church Father comments on this verse
It will commence from the wilderness of Sin, adjacent to Edom, with the sea marking the eastern limit. In essence, this indicates that the boundary extends from the wilderness of Sin, situated near Edom, to the Red Sea.
Passages read together with this verse.