1)
What is the meaning of "veha'Leviyim ba'Melaches"?
1.
'Rashi', Malbim: It means ba'Melachtam ? some sing and some guard gates, according to David's assignment.
2.
Radak: It is with the Kelim proper for them, i.e. musical instruments 1 .
1
Radak: There should be a Dagesh in the Mem; it is soft for ease of pronunciation. The same applies to "Basar Chai ba'Seis" (Vayikra 13:10) and other words.


