What is the meaning of "v'Haysah ha'Ir Cherem"?
Rashi: It is Hekdesh.
Radak: It will not be rebuilt, and no one may benefit from all that is in the city.
Who decided to make the Cherem?
Rashi (Sanhedrin 44a): Yehoshua decided by himself 1 [and Hashem rebuked him, for Yisrael stumbled in it].
Radak: Presumably, Hashem told Yehoshua so, even though the Navi does not record this. Many such matters are not recorded. Yehoshua would not say so on his own!
Radak, citing Yerushalmi Brachos 9:5: Hashem agreed to Yehoshua's decree.
There was a Mitzvah to kill all the residents of Eretz Kena'an. Why did this not apply to Rachav?
Malbim: #1: Because she hid the spies, she is not included in the city and its spoils.
Malbim #2: She converted in front of the spies and accepted Emunah in Hashem before they crossed the Yarden. All agree that we were commanded to accept converts then. However, conversion would not save her property or family. They were spared only because she hid the spies.
Why did Yehoshua not say that they may not kill Rachav due to the spies' Shevu'ah?
Malbim: The nation did not swear, only the spies did. Their Shevu'ah does not obligate the nation, just the spies are obligated due to her Shevu'ah.
Why does it say "Hechbasah", which implies that she hid something feminine?
Radak: The word has two 'signs' of being feminine, like "Yeshu'asah 1 ", "Ezrasah" (Yonah 2:10, Tehilim 63:8). Every doubling strengthens the matter. In this case, she hid them well.
Perhaps this should say "Lishu'asah" (Tehilim 80:3).
QUESTIONS ON RASHI
Rashi writes that the city will be Hekdesh. What is the reason for this?
Rashi: Shabbos is Kodesh. It is proper that booty taken on Shabbos be Kodesh.
Radak: It was the first part of the land conquered. Yehoshua thought to make it [Kodesh to Hashem] like Terumah, just like a woman separates Chalah from the beginning of her dough.
Malbim: Since the conquest will be miraculous via Hashem, it is proper that the spoils be Kodesh to Hashem, the conqueror.