Why does it say "v'Sabosem" and "Hakef"?
Malbim: Sivuv applies even to partial circling. Hakef refers to totally going around.
Who are "Kol Anshei ha'Milchamah" who will circle the city?
Abarvenel: This excludes only women, children and old people. Refer to 6:8:1:1.
Alshich: It is only the Chalutz (Bnei Gad, Bnei Reuven and Chetzi Menasheh. However, the people erred about this; refer to 6:8:1:1.)
Why is there a Yud in "Hakef"?
Radak: Sometimes there is a Yud after a Tzeirei, e.g. "v'Saged li'Vnei Yisrael" (Shemos 19:3).
Why did they circle the city for seven days, with seven Kohanim blowing seven Shofaros, and circling seven times on day seven?
Radak: We cannot ask why Hashem commanded this way. People who know, they understand the significance of seven. 1
Radak: We find that Bil'am commanded to build seven Mizbechos, and to offer seven bulls and seven rams. Seven is the chosen number regarding days, months and years. (How it is chosen regarding months? Most of the Yamim Tovim are in the seventh month. The minimal term of pregnancy for a viable baby is seven months (part of a month counts as a month). A girl becomes Bogeres at the start of her seventh month after becoming a Na'arah. Hashem created the world in the seventh month from when He had the intent to do so (Tosfos Rosh Hashanah 27a). I do not understand how time is measured before Creation. Hashem does not change, so time does not apply to Him!
Why did they blow Teru'ah on day seven, and the wall fell?
Radak: The Teru'ah was to scare the enemy and make them panic. The wall fell to show that Hashem fights for Yisrael, and not via sword and spear.