1)
What is the meaning of "v'Al Techas"?
1.
Rashi: Do not Techaseh (cover up). Similarly, "v'Sod Acher Al Tegal" is like Al Tegaleh.
2)
How should their sin not be erased?
1.
Malbim (here and Yirmeyah 18:23): This is like "v'Chatasam? Al Temchi." Even after their punishment, [their sin] should not be erased. It should be written in front of You for a permanent remembrance!
3)
Did they make people angry?
1.
Rashi: They showed anger at the builders, to mock them. Malbim ? this was in order to interfere with their work.
