Who are "Ne'arai"?
Rashi: The Giborim working on the wall.
Malbim: Nechemyah's youths and servants. Only they were divided (half worked, and half held weapons). This is because some were skilled warriors, and held a spear in one hand and a shield in the other, or archers who wore armor. One cannot work like this! Everyone else worked with one hand, and held a weapon in the other. They did not have a shield, armor or arrows (they were not trained archers), just [a spear or sword] to pierce the enemy if the enemy will come.
Why does it say "veha'Remachim", with the prefix Vov ?
Rashi, Ibn Ezra #1: The prefix Vov is extra, like "v'Ayah v'Anah."
Ibn Ezra #2: The words should be rearranged. It means, Machazikim ha'Maginim veha'Remachim. This Perush is primary.
Ibn Ezra #3: It means, veha'Remachim b'Yadam (and the spears were in their hands).
What did the Sarim do?
Rashi: They were connected to all of Shevet Yehudah, to be careful in war.
Malbim: They and all of Beis Yehudah were Acharei, i.e. gathered by Nechemyah. They did not spread out to their work.
