Тосефта к Бамидбар 5:2

At a time that the Passover offering is eaten in a state of impurity (i.e., when the majority of the nation has been defiled due to contact with a corpse, see Pes. 67b:8), one who bears corpse-impurity may enter the Temple Courtyard and partake of [the Paschal lamb]. [However,] zavim and zavot (i.e., men and women who had abnormal discharges), niddot (menstruants), and yoldot (women who recently gave birth) may not enter, and if they did enter, behold, they are liable. Rabbi Eliezer says, if they entered, behold, they are exempt, as it is said (Num. 5:2), "And you shall send out from the camp any leper and any zav [and anyone with corpse-impurity]," [in order to teach that] whenever one with corpse-impurity is liable, zavim and lepers are liable, [and] whenever one with corpse-impurity is not liable, zavim and lepers are not liable. Whenever the Passover offering is brought (alt., "eaten," see Lieberman) in a state of impurity, one who bears corpse-impurity may enter the Temple Courtyard and slaughter, [but] zavim and zavot, niddot and yoldot -- behold, they may not slaughter, and if they did slaughter, behold, they are liable. Rabbi Shimon says in the name of Rabbi Yehoshua, if they slaughtered, behold, they are exempt, as it is said (Lev. 7:19-20), "any pure person may eat the flesh, but a person who eats from a peace-offering that belongs to God [while impure, that person is cut off from his people]." [Thus, a Passover offering] that is slaughtered [by zavim, etc.] for pure persons renders them liable on its account due to impurity, [and] that which is slaughtered for impure persons does not render them liable on its account due to impurity.