Sifrei Bamidbar

“And the L-rd spoke to Moses, saying: Command the children of Israel that they send out of the camp every leper (metzora) and everyone with a (genital discharge (zav), and everyone that is unclean by (contact with) a body (tamei meth).” Why was this section stated? (For) from “A man, if he becomes unclean and does not purify himself, that soul shall be cut off from the midst of the congregation, for he has defiled the sanctuary of the L-rd,” we hear the punishment; but we have not heard the exhortation. It is, therefore, written “Command the children of Israel that they send out of the camp … (3) and they shall not make unclean their camps in which I dwell.” This (3) is the exhortation that the unclean not enter the sanctuary in a state of uncleanliness.

“Command”: The command is immediately, for present performance and for future generations. You say thus, but perhaps it is only for future performance! It is, therefore, (to negate this) written “Command the children of Israel that they send … “And the children of Israel did so, sending them outside the camp” — whence we derive that the command is for immediate performance. And whence do we derive that it is (also) for future generations? From “Command the children of Israel that they take to you clear olive oil … (3) … an eternal statute for your generations.” — But how do we derive (the same) for all the commands in the Torah? R. Yishmael says: Since we find unqualified commands in the Torah, and one of them was qualified as being for present performance and for future generations, we derive the same for all the mitzvoth in the Torah. R. Yehudah b. Bethira says: “command” in all places connotes impulsion (to the act), as it is written “And command Joshua and strengthen him and fortify him” — whence we learn “We strengthen only the (internally) strengthened,” and “We impel only the (internally) impelled.” R. Shimon b. Yochai says: “Command” in all places entails expense, as it is written “Command the children of Israel that they take to you pure olive oil,” “Command the children of Israel that they give to the Levites from the inheritance, etc.” “Command the children of Israel and say to them: My offering, My bread, for My fires” — whence we see that “command” in all places entails expense. Except in one; and which is that? “Command the children of Israel and say to them: When you come to the land of Canaan, etc.” — where the intent is: Impel them to the division of the land. Rebbi says: “Command” in all places is exhortation, as it is written “And the L-rd G-d commanded (i.e., exhorted) the man, saying … but of the tree of knowledge of good and evil, you shall not eat.”