Is this Chamas mentioned elsewhere?
Radak: It is in Zecharyah "v'Gam Chamas Tigbal Bah" (9:2). It is not Chamas written in the Torah.
Malbim: It is Chamas in the Torah, but now the border will be north of it.
Why does it mention Damesek?
Radak: It will be part of the border ? "v'Damesek Menuchaso" (Zecharyah 9:1).
What is "Chatzer ha'Tichon"?
Rashi citing Targum Yonasan: The pond of Agva'ei.
Radak: It is the name of a place.
What do we learn from "Asher Al Gevul Chavran"?
Rashi: This is the border of Damesek in the east, near the corner.
Malbim: In the north, Eretz Yisrael will extend until a line going west from Damesek. In addition, there will be a strip from Damesek until Gevul Chavran. This is "v'Tzafon Tzafonah" (17).
