1)
Why does it say "Kol Mevin"?
1.
'Rashi': Mevin applies to Shirah, e.g. "Mevin Im Talmid", "Sar ha'Leviyim b'Masa Yasor b'Masa Ki Mevin Hu."
2)
What is the significance of 288?
1.
Radak (1), Malbim: There were 12 in each of the 24 Mishmaros.
