1)
Who are "Ish v'Na'aro"?
1.
Rashi: Every builder and a bachelor with him.
2)
Why does it add "v'Hayu Lanu ha'Lailah Mishmar veha'Yom Melachah"?
1.
Berachos 2b: One might have thought that night begins before Tzeis ha'Kochavim (and day begins after dawn), and they were working more than usual (to build the wall of Yerushalayim). Our verse shows that this is not so.


