1)
Shelah was born before Peretz and Zerach. Why is he taught after them?
1.
'Rashi': For the honor of Beis David, Bnei Tamar (Peretz and Zerach) were taught first, for David descended from them. After finishing Peretz and Zerach, it now lists the [important] families of Shelah in [Ezra's] time.
2)
What is "Avodas ha'Butz"?
1.
'Rashi': It is making curtains for the Mikdash.
2.
Radak: They worked with linen. Malbim - Butz is precious linen.
