1)
Why does it say "v'Neged Beiso"?
1.
Rashi: His portion of the wall to build was near his house. His house was near the city wall. Ibn Ezra ? it should say "Hechezik"; the word is omitted.
2.
Malbim: He strengthened the entire wall opposite his house, apart from what he strengthened by Refayah, which was outside his house, to the east.
