1)
Why did He say "va'Tisa Marom Einecha"?
1.
Malbim (Yeshayah 37:23): You did not intend only to anger the nation, rather, to revile Hashem Himself.
2)
Why does it say "Al Kadosh Yisrael"?
1.
Radak: This is like El 1 Kadosh Yisrael.
1
And so it says in Yeshayah (37:23).