(א) בָּרוּךְ אַתָּה ה' אֱלהֵינוּ מֶלֶךְ הָעולָם אֲשֶׁר קִדְּשָׁנוּ בְּמִצְותָיו וְצִוָּנוּ לַעֲסוק בְּדִבְרֵי תורָה:
(1) Blessed are You, Lord, our God, King of the Universe, Who has sanctified us with his commandments and commanded us to be involved with words of Torah.
(א) וַיֹּ֤אמֶר יְהוָה֙ אֶל־מֹשֶׁ֔ה אֱמֹ֥ר אֶל־הַכֹּהֲנִ֖ים בְּנֵ֣י אַהֲרֹ֑ן וְאָמַרְתָּ֣ אֲלֵהֶ֔ם לְנֶ֥פֶשׁ לֹֽא־יִטַּמָּ֖א בְּעַמָּֽיו׃ (ב) כִּ֚י אִם־לִשְׁאֵר֔וֹ הַקָּרֹ֖ב אֵלָ֑יו לְאִמּ֣וֹ וּלְאָבִ֔יו וְלִבְנ֥וֹ וּלְבִתּ֖וֹ וּלְאָחִֽיו׃ (ג) וְלַאֲחֹת֤וֹ הַבְּתוּלָה֙ הַקְּרוֹבָ֣ה אֵלָ֔יו אֲשֶׁ֥ר לֹֽא־הָיְתָ֖ה לְאִ֑ישׁ לָ֖הּ יִטַּמָּֽא׃ (ד) לֹ֥א יִטַּמָּ֖א בַּ֣עַל בְּעַמָּ֑יו לְהֵ֖חַלּֽוֹ׃ (ה) לֹֽא־יקרחה [יִקְרְח֤וּ] קָרְחָה֙ בְּרֹאשָׁ֔ם וּפְאַ֥ת זְקָנָ֖ם לֹ֣א יְגַלֵּ֑חוּ וּבִ֨בְשָׂרָ֔ם לֹ֥א יִשְׂרְט֖וּ שָׂרָֽטֶת׃ (ו) קְדֹשִׁ֤ים יִהְיוּ֙ לֵאלֹ֣הֵיהֶ֔ם וְלֹ֣א יְחַלְּל֔וּ שֵׁ֖ם אֱלֹהֵיהֶ֑ם כִּי֩ אֶת־אִשֵּׁ֨י יְהוָ֜ה לֶ֧חֶם אֱלֹהֵיהֶ֛ם הֵ֥ם מַקְרִיבִ֖ם וְהָ֥יוּ קֹֽדֶשׁ׃
(1) Hashem said to Moses: Speak to the priests, the sons of Aaron, and say to them: None shall defile himself for any [dead] person among his kin, (2) except for the relatives that are closest to him: his mother, his father, his son, his daughter, and his brother; (3) also for a virgin sister, close to him because she has not married, for her he may defile himself. (4) But he shall not defile himself as a kinsman by marriage, and so profane himself. (5) They shall not shave smooth any part of their heads, or cut the side-growth of their beards, or make gashes in their flesh. (6) They shall be holy to their God and not profane the name of their God; for they offer Hashem’s offerings by fire, the food of their God, and so must be holy.
(ה) לא יטמא בעמיו. בְּעוֹד שֶׁהַמֵּת בְּתוֹךְ עַמָּיו, יָצָא מֵת מִצְוָה (שם):
(5) לא יטמא בעמיו THERE SHALL NONE BE DEFILED BY THE DEAD AMONG HIS PEOPLES — This means, as long as the dead is among his peoples (i. e. so long as there are some of his people — Jews — who can occupy themselves with his burial) thus excluding the case of a מת מצוה (a corpse of a person whose relatives are unknown or which lies in a place where there are no Jews, nor are there any in the near vicinity; cf. Nazir 43b) in which case the priest is allowed to make himself unclean by handling the corpse (Sifra, Emor, Section 1 3).
(ג) לה יטמא. מִצְוָה (ספרא; זבחים ק'):
(3) לה יטמא — This is a command, [and the translation is: FOR HER HE SHALL DEFILE HIMSELF, not, “he may defile himself”] (Sifra, Emor, Section 1 12; Zevachim 100a).
(א) לא יטמא בעל בעמיו להחלו והטעם שלא יטמא הכהן כי אם לקרוביו הוא כי אמנם הכהן הוא בעל בעמיו להבין ולהורות כי שפתי כהן ישמרו דעת ותורה יבקשו מפיהו וראוי לאיש כזה לנהוג נשיאות כי היכי דלשתמען מיליה ואין ראוי שיחלל הכנתו אל מקדש וקדשיו כדי לכבד המתים הבלתי קרובים כאמרם ז''ל (סנהדרין פכ''ג) שהקבורה וההספד למת הם יקרא דשכבי. אמנם לקרובים התיר להטמא כי כבודם הוא כבודו:
(1) לא יטמא בעל בעמיו להחלו, the reason why a priest is not to defile himself through contact with the dead except those of his next of kin, is that also the priest is indeed a בעל בעמיו, a distinguished, highly placed member of his people, it is his task to understand and teach these laws as we know from Maleachi 2,7 “for the lips of the priest are meant to guard knowledge, and Torah and the people will enquire concerning these from his mouth.” This makes him a person to be treated in the manner one treats a politically highly placed person, a king. Seeing he is supposed to be ever ready to serve the King of Kings, in His Temple, it is not appropriate for such a person to desecrate his status even temporarily in order to participate in the burial rites of ordinary people. According to our sages in Sanhedrin 47 the prime purpose of burying and eulogising the dead is to render honour to them. This conflicts with the honour the priests have to accord to G’d on an ongoing basis. However, he is permitted to become impure for his relatives, for their honour is his honour.
(ג) [ג] מנין לרבות את הטומאות הפורשות מן המת? תלמוד לומר "ואמרת אלהם"-- לרבות את הטומאות הפורשות מן המת. "לנפש לא יטמא בעמיו"-- בזמן שעמיו שם אינו מטמא, מִטמא הוא למת מצוה.
(3) 3) Whence is derived for inclusion all the tumah segments that separate from the body? From "and you shall say to them" — to include these. "For a dead body he shall not become tamei among his people": When his people are there [i.e., when there are non-priests who can tend to the body, he is not to become tamei, but he is to become tamei for a meth mitzvah (a body which has no one to tend to it.)
(יג) [יג] "לה יטמא"-- מטמא הוא על הודאי ואינו מטמא על הספק. "לה יטמא"-- אינו מטמא לאחרים עמה, שלא יאמר "הואיל ונטמאתי, אלקט עצמות פלוני בידי".
(13) 13) "for him shall he make himself tamei": for (one who is his sister of) a certainty; and he does not make himself tamei for one who is not his sister or a certainty. "for her shall he make himself tamei": and not for others with her, i.e., he should not say: Since I have already made myself tamei (for her), I shall collect the bones of so and so.
... לְפִיכָךְ אָסוּר לְכֹהֵן לְהִתְטַמֵּא לְמֵת אֲפִלּוּ בְּעֵת שֶׁמִּתְטַמֵּא לִקְרוֹבָיו שֶׁנֶּאֱמַר (ויקרא כא ג) "לָהּ יִטַּמָּא" אֵינוֹ מִטַּמֵּא לַאֲחֵרִים עִמָּהּ. שֶׁלֹּא יֹאמַר הוֹאִיל וְנִטְמֵאתִי עַל אָבִי אֲלַקֵּט עַצְמוֹת פְּלוֹנִי אוֹ אֶגַּע בְּקֶבֶר פְּלוֹנִי. לְפִיכָךְ כֹּהֵן שֶׁמֵּת לוֹ מֵת צָרִיךְ לְהִזָּהֵר וּלְקָבְרוֹ בְּסוֹף בֵּית הַקְּבָרוֹת כְּדֵי שֶׁלֹּא יִכָּנֵס לְבֵית הַקְּבָרוֹת וְלֹא יִתְטַמֵּא בְּקִבְרוֹת אֲחֵרִים כְּשֶׁיִּקְבֹּר מֵתוֹ:
...Therefore, it is forbidden for a priest to defile himself with a corpse even while he is defiling himself with one of his relatives, because it says, ‘“For her may he defile himself”—he may not defile himself to others in addition to her. A person should not say, ‘Since I am already defiled, I will gather so-and-so’s bones.’”... therefore, when a priest’s relative dies, he must take care to bury the body at the edge of the cemetery such that he does not enter the cemetery and defile himself to others as he buries his dead....
(translation by Rabbi Ethan Tucker)
אמר רב חסדא אמר רב נקטע ראשו של אביו אינו מטמא לו מ"ט אמר קרא (ויקרא כא, ב) לאביו בזמן שהוא שלם ולא בזמן שהוא חסר א"ל רב המנונא אלא מעתה קאזיל בפקתא דערבות ופסקוה גנבי לרישיה הכי נמי דלא ליטמא ליה אמר ליה מת מצוה קאמרת השתא יש לומר באחריני מיחייב באביו לא כל שכן והאי מת מצוה הוא והתניא איזהו מת מצוה כל שאין לו קוברין קורא ואחרים עונין אותו אין זה מת מצוה והא אית ליה ברא כיון דקאזיל באורחא כמי שאין לו קוברים דמי
§ Rav Ḥisda said that Rav said: If the head of his father, or any other relative for whom a priest becomes impure, was severed, he may not become impure to bury him. What is the reason? The verse states: “None shall become impure for the dead among his people, except…for his father” (Leviticus 21:1–2), which applies when his father is whole, and not when he is lacking. Rav Hamnuna said to Rav Ḥisda: If that is so, when he was walking in the valley [pakta] of Aravot, and robbers severed his head, will you also say that his son the priest does not become impure to bury him because he is not whole? Rav Ḥisda said to him: You speak of a corpse with no one to bury it [met mitzva]. Now,one can say that to bury others, i.e., non-relatives, he is obligated to become ritually impure, as even priests and nazirites must become impure to bury an unattended corpse, then with regard to a met mitzva who is his father is it not all the more so the case that he must become impure to bury him even if his head is severed? The Gemara asks: And is this a met mitzva? But isn’t it taught in a baraita: Which is a met mitzva for whom a priest must become impure? It is anyone who does not have others to bury him. If he is in a place where if he calls, others would answer him, that is not a met mitzva. And he has a son - but since he was walking along the way, he is considered like one who does not have people to bury him.
ואמר רב יהודה אמר רב מת בעיר כל בני העיר אסורין בעשיית מלאכה רב המנונא איקלע לדרומתא שמע קול שיפורא דשכבא חזא הנך אינשי דקא עבדי עבידתא אמר להו ליהוו הנך אינשי בשמתא לא שכבא איכא במתא אמרו ליה חבורתא איכא במתא אמר להו אי הכי שריא לכו
And Rav Yehuda said in the name of Rav: When a person dies in a city, all of the residents of that city are prohibited from performing work until he has been buried. The Gemara relates that when Rav Hamnuna once happened to come to a place called Darumata he heard the sound of a shofar announcing that a person had died in the town. When he saw some people doing work he said to them: Let these people be under an excommunication. Is there not a dead person in town? They said to him: There are separate groups in the town, each one responsible for its own dead. Knowing that the deceased was not from our group, we continued our work. He said to them: If so, it is permitted to you, and he revoked his excommunication.
from: Kohanim and Death: The Range of Possibilities in Halakhic Interpretation, By Rabbi Ethan Tucker, https://www.hadar.org/torah-resource/kohanim-and-death#source-4339
I most powerfully experienced the point of this rigid sort of approach, and what it is meant to accomplish, in the context of my motherinlaw’s funeral. After the burial at the cemetery, we returned back to her home, where a few people were already at work setting up the הבראה סעודת —the first meal eaten by the mourners once they return home. One of the women asked one of the men who was setting up whether he was with the caterers. He replied, “No, I am a kohen, so I can never go to the funerals; instead, I set up the food for people when they return.” I recall it as an overwhelming moment, when the purpose of this mitzvah leapt out of the scrolls and pages of law into the world of living empathy it was meant to create. The kohanim don’t just avoid death in order to fulfill a theoretical biblical mandate for life. Their near complete exclusion from the rituals of death is meant to keep them focused on actually creating a culture of life, untainted by the brokenness and sorrow that surround loss, and the horror of confronting a soulless, lifeless human body. In the world of the Temple, this would have been a focus on the avodah, the sacrificial service conducted in an aesthetically perfect environment that bestowed a sense of life and renewal on all who participated in it. In our own world, it may be redirected to the mourners’ homes, where they, with no graveside dirt on their hands, are able to welcome the bereaved back into the world of the living.