Levítico 10:19 Halacá: Mishneh Torah, Mourning, Sefer HaMitzvot & Sefer HaChinukh

It is a positive commandment to mourn for one's closest relatives, as it is said (Lev 10:19) "...had I eaten sin offering today would the Lord have approved." And mourning is not based on Scripture except for the first day only because it is the day of the death and the day of the funeral. But the rest of the seven days are not torah-mandated, even though it says (Gen 50:10) "...and he mourned for his father seven days." - when the Torah was given the law was renewed. And Moses our teacher established the seven days of mourning and the seven days of celebrating for Israel.

That He prohibited us from eating second tithe when grieving - even in Jerusalem - until it has been redeemed. And that is His saying, "I did not eat of it when grieving" (Deuteronomy 26:14). And the language of the Mishnah in Bikkurim (Bikkurim 2:2) is that "The [second] tithe and firstfruits require being brought to [the appointed] place; they require confession; and they are forbidden to one grieving." And likewise anyone grieving is forbidden with regards to all consecrated foods from this verse, as well as from it being written in the Torah, "and such things have befallen me" (Leviticus 10:19). And the regulations of this commandment - meaning to say, grieving - have already been explained in the eighth [chapter] of Pesachim and the second [chapter] of Zevachim. And one who eats second tithe or tithes while grieving is lashed. (See Parashat Ki Tavo; Mishneh Torah, Second Tithes and Fourth Year's Fruit 3.)

The commandment of the matter of the impurity of the priests for their relatives, and included in it is that each one in Israel should mourn for their six relatives [the identity of which is] well-known: That the priests should become impure for the dead bodies (the relatives) that are mentioned in the Torah, as it is stated (Leviticus 21:3), “for her, he shall become impure.” And this is a positive commandment, as so did the explanation come. And so is it explained in Sifra, Emor, Section 1:12, “‘For her, he shall become impure’ — is a commandment. If he does not want to become impure, we make him impure by force.” And were it not that we received this explanation from our Sages, I would have reasoned to say that it be optional — if he wants, he becomes impure; if he does not want, he does not become impure — since Scripture prevented him from becoming impure for the rest of his relatives. And I would have said that regarding these mentioned in the section of the Torah, they were permitted to become impure if they wanted. Hence the explanation about it came to us — that it is not optional, but rather a commandment. And the Sages, may their memory be blessed, mentioned a story that Yosef the priest came when his wife died on the eve of Pesach and he did not want to become impure, and the Sages pushed him and made him impure by force. And Rambam, may his memory be blessed, wrote (Sefer HaMitzvot, Positive Commandments 37), “And this itself is the commandment of mourning — meaning to say that each person in Israel is obligated to mourn for his relatives, meaning the six relatives mentioned in Scripture.” And the verse that the Rabbi brought [as a source] (Mishneh Torah, Laws of Mourning 1:1) for the commandment of mourning is that which is stated by Aharon, “if I had eaten the sin-offering today, would it have been good in the eyes of the Lord?” (Leviticus 10:19). And he said, “And for the strengthening of this commandment did they elucidate about the priest that he is warned about impurity, that he should become impure regardless like other Israelites, in order that the laws of mourning not become weakened. And it was already elucidated that mourning of the first day is by Torah writ — and that is the day of death and burial. And they said in the elucidation in Moed Katan 14b [that] it is not practiced on the holiday — the positive commandment of the many comes and pushes off the positive commandment of the individual. And behold, it is elucidated [from this] that the obligation of mourning is from Torah writ and that it is a positive commandment — but only on the first day. And the remaining six [days] are rabbinic. And even a priest observes mourning on the first day, as he becomes impure for his relatives. And understand this.” To here [are his words].