What does the Torah mean when it writes "Al Tachrisu es Sheivet ha'Kehasi"?
Seforno: It means that they should not allow the B'nei K'has to apply a policy of 'First come, first served', when coming to carry the holy vessels, because then, in their eagerness to perform the Mitzvah, they would push each other and desecrate the Kodesh, thereby resulting in their deaths. 1 But rather that Aharon and his sons, when coming to cover the vessels, should designate each ben K'has to the specific task that he was to perform.
Yerushalmi Bikurim, 2:1: From a combination of this Pasuk ("Al Tachrrisu ... ") and the Pasuk in Beha'aloscha, 8:25, which gives the retiring age of the Levi'im as fifty, we learn that the definition of Kareis is to die at the age of fifty. 2
Why does the Torah refer to K'has as 'Sheivet'?
Moshav Zekenim (citing R. Yehudah ha'Chasid): Just as a tribe that is designated to encamp in the south is forbidden to encamp in the north, so may the families of Levi not switch their order of encampment. 1
In tha case, Gershon and Merari too, are called a Sheivet and certainly the other eleven tribes - yet we do not find the word "Sheivet" in connecion with any Sheivet - even K'has, anywhere else in the entire Parshah?
