The Torah in Parashat Mesora (Vayikra 15:2) assigns a status of Tum’a (impurity) to a “Zav” – a man who experiences an unusual bodily discharge. The Sefer Ha’hinuch explains that this discharge differs from seminal emissions, as it leaves the body without the man experiencing desire or pleasure. He adds that this discharge resembles the water used when producing barley dough. A man who experiences such a discharge – even just a single drop – on two occasions has the status of a Zav, and is considered impure. The Sefer Ha’hinuch lists this status of impurity as the 178 th Biblical command. Any surface that a Zav sits on, lies upon, or rides (such as a saddle) during his period of impurity becomes Tameh. The Sefer Ha’hinuch posits that the Torah established this status of Tum’a because this unusual discharge can result from overindulgence in food. Although we are certainly entitled and encouraged to eat as necessary to maintain our health and strength, we are to avoid excessive indulgence in physical enjoyment. The Torah therefore assigned a status of Tum’a to one who experiences the effects of overindulgence, to convey the message that he must moderate his food intake and not inappropriately indulge. This law applies in all places and at all times, even nowadays, though in the absence of the Bet Ha’mikdash, this status has no practical relevance, as we in any event do not go to the Bet Ha’mikdash or eat hallowed food. In the times of the Bet Ha’mikdash, a man who experienced such a discharge and went to the sacred domain of the Mikdash, or partook of hallowed food, would be in violation of this affirmative command. The Torah later (15:13) commands that if a man experiences such an emission three times, then in order to regain his state of purity, he must not only immerse in a Mikveh, but also bring special sacrifices. These sacrifices are to be offered on the eighth day after experiencing these emissions. The Sefer Ha’hinuch lists the offering of these sacrifices as the 179 th Biblical command. The Zav is required to offer two birds – one as a Hatat (sin offering) and the other as an Ola (burnt offering). Even after the Zav immerses in a Mikveh, he remains Tameh until these sacrifices are offered. His interim status until the sacrifices are offered is called “Mehusar Kapara.” There is an exceptional Halacha allowing the required sacrifices to be offered on behalf of a “Mehusar Kapara” even without him knowing. Generally speaking, a sacrifice must be offered by the individual willingly, with his knowledge. However, in a situation where the Torah requires bringing a sacrifice to complete the process of purification, once the individual designates the animals as his sacrifice, they may be offered on his behalf even without his knowledge, and he is then considered Tahor (pure). The Hazon Ish (Rav Avraham Yeshaya Karelitz, 1878-1953) explains this unique Halacha based on the principle of “Zachin Le’adam She’lo Be’fanav” – an acquisition may be made on a person’s behalf without his knowledge, if this is to his benefit. Since the offering of these sacrifices is clearly to the individual’s benefit, they may be offered even without his knowledge. This Misva, of course, applies only in the times of the Bet Ha’mikdash. If a man experiences three emissions that render him a Zav and require him to offer these sacrifices, and he fails to do so, then he has violated this affirmative command.