Halacha

הלכה א
אֵלוּ שֶׁאָדָם חַיָּב לְהִתְאַבֵּל עֲלֵיהֶן דִּין תּוֹרָה. אִמּוֹ וְאָבִיו בְּנוֹ וּבִתּוֹ וְאָחִיו וַאֲחוֹתוֹ מֵאָבִיו. וּמִדִּבְרֵיהֶם שֶׁיִּתְאַבֵּל הָאִישׁ עַל אִשְׁתּוֹ הַנְּשׂוּאָה. וְכֵן הָאִשָּׁה עַל בַּעְלָהּ. וּמִתְאַבֵּל עַל אָחִיו וְעַל אֲחוֹתוֹ שֶׁהֵן מֵאִמּוֹ:
כסף משנה
1.
These are the relatives for whom a person is obligated to mourn according to Scriptural Law: His mother, his father, his son, his daughter, his paternal brother and paternal sister. According to Rabbinic Law, a man should also mourn for his wife if she dies while they are married. And a woman should mourn for her husband. Similarly, a person should mourn for a maternal brother and sister.

הלכה ב
אֲפִלּוּ הַכֹּהֵן שֶׁאֵינוֹ מִתְטַמֵּא לְאָחִיו וַאֲחוֹתוֹ מֵאִמּוֹ וְלַאֲחוֹתוֹ הַנְּשׂוּאָה אַף עַל פִּי שֶׁהִיא מֵאָבִיו. מִתְאַבֵּל הוּא עֲלֵיהֶן. וְאִם הָיְתָה אֲחוֹתוֹ זוֹ הַנְּשׂוּאָה מֵאָבִיו הֲרֵי הוּא מִתְאַבֵּל עָלֶיהָ דִּין תּוֹרָה:
כסף משנה
2.
Even a priest who does not become impure for his maternal brother and sister or for his paternal sister who is married, mourns for them. For his married paternal sister who is married, he is required to mourn by Scriptural Law.

הלכה ג
בְּנוֹ אוֹ אָחִיו הַבָּא מִן הַשִּׁפְחָה וּמִן הַנָּכְרִית אֵינוֹ מִתְאַבֵּל עֲלֵיהֶן כְּלָל. וְכֵן מִי שֶׁנִּתְגַּיֵּר הוּא וּבָנָיו אוֹ נִשְׁתַּחְרֵר הוּא וְאִמּוֹ אֵין מִתְאַבְּלִין זֶה עַל זֶה. וְכֵן אִשְׁתּוֹ אֲרוּסָה אֵינוֹ מִתְאַבֵּל עָלֶיהָ וְלֹא אוֹנֵן וְכֵן הִיא לֹא אוֹנֶנֶת וְלֹא מִתְאַבֶּלֶת עָלָיו:
כסף משנה
3.
A person who has a son or a brother born by a maid-servant or a gentile woman should not mourn for them at all. Similarly, when a person and his sons convert or a person and his mother are freed from slavery, they do not mourn for each other.
Similarly, a person does not observe either the rites of aninut or the mourning rites for a wife whom he has consecrated, but not married. Similarly, she does not observe either of these rites for him.

הלכה ד
כָּל קְרוֹבִים שֶׁהוּא חַיָּב לְהִתְאַבֵּל עֲלֵיהֶן הֲרֵי זֶה מִתְאַבֵּל עִמָּהֶם בִּפְנֵיהֶם מִדִּבְרֵי סוֹפְרִים. כֵּיצַד. הֲרֵי שֶׁמֵּת בֶּן בְּנוֹ אוֹ אֲחִי בְּנוֹ אוֹ אֵם בְּנוֹ חַיָּב לִקְרֹעַ בִּפְנֵי בְּנוֹ וְלִנְהֹג אֲבֵלוּת בְּפָנָיו אֲבָל שֶׁלֹּא בְּפָנָיו אֵינוֹ חַיָּב. וְכֵן בִּשְׁאָר הַקְּרוֹבִים:
כסף משנה
4.
Whenever a person is obligated to mourn for a relative, he also mourns with that relative in his presence according to Rabbinical Law.
What is implied? If a person's grandson, his son's maternal brother, or son's mother dies, he is obligated to rend his garments in the presence of his son and follow the mourning rites while in his presence. Outside his presence, he is not obligated. Similar laws apply with regard to other relatives.

הלכה ה
אִשְׁתּוֹ הַנְּשׂוּאָה אַף עַל פִּי שֶׁהוּא מִתְאַבֵּל עָלֶיהָ אֵינוֹ מִתְאַבֵּל עִמָּהּ עַל שְׁאָר קְרוֹבִים אֶלָּא עַל אָבִיהָ וְעַל אִמָּהּ מִשּׁוּם כְּבוֹד אִשְׁתּוֹ נוֹהֵג אֲבֵלוּת עֲלֵיהֶן בְּפָנֶיהָ. כֵּיצַד. מִי שֶׁמֵּת חָמִיו אוֹ חֲמוֹתוֹ כּוֹפֶה מִטָּתוֹ וְנוֹהֵג אֲבֵלוּת עִם אִשְׁתּוֹ בְּפָנֶיהָ אֲבָל לֹא שֶׁלֹּא בְּפָנֶיהָ. וְכֵן הָאִשָּׁה שֶׁמֵּת חָמִיהָ אוֹ חֲמוֹתָהּ נוֹהֶגֶת אֲבֵלוּת בְּפָנָיו. אֲבָל שְׁאָר קְרוֹבִים כְּגוֹן שֶׁמֵּת אֲחִי אִשְׁתּוֹ אוֹ בְּנָהּ וְהָאִשָּׁה שֶׁמֵּת אֲחִי בַּעְלָהּ אוֹ בְּנוֹ אֵין מִתְאַבְּלִין זֶה עַל זֶה. וְכֵן יֵרָאֶה לִי שֶׁאִם מֵתָה אֵשֶׁת קְרוֹבוֹ אוֹ בַּעַל קְרוֹבָתוֹ כְּגוֹן שֶׁמֵּתָה אֵשֶׁת בְּנוֹ אוֹ בַּעַל בִּתּוֹ אֵינוֹ חַיָּב לְהִתְאַבֵּל עֲלֵיהֶן. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
5.
With regard to a wife with whom one is married: Although one must mourn for her, he does not mourn together with her for her other relatives with the exception of her father and her mother. He observes the rites of mourning for them in her presence.
When a man's father-in-law or mother-in-law dies, he overturns his bed and observes the mourning rites together with his wife within her presence, but not outside her presence. Similarly, when a woman's father-in-law or mother-in-law dies, she observes the rites of mourning in her husband's presence. With regard to other relatives, by contrast, e.g., the brother of one's wife or her son dies or when the brother of one's husband or his son dies, they do not observe the mourning rites in respect for each other.
Similarly, it appears to me that if the wife of a person's relative dies or the husband of one of his relatives, e.g., the wife of one's son or the husband of one's daughter, one need not observe mourning rites for them. Similar concepts apply in all analogous situations.

הלכה ו
כַּמָּה חֲמוּרָה מִצְוַת אֲבֵלוּת. שֶׁהֲרֵי נִדְחֵית לוֹ הַטֻּמְאָה מִפְּנֵי קְרוֹבָיו כְּדֵי שֶׁיִּתְעַסֵּק עִמָּהֶן וְיִתְאַבֵּל עֲלֵיהֶן. שֶׁנֶּאֱמַר (ויקרא כא ב) "כִּי אִם לִשְׁאֵרוֹ הַקָּרֹב אֵלָיו לְאִמּוֹ" וְגוֹ' (ויקרא כא ג) "לָהּ יִטַּמָּא" מִצְוַת עֲשֵׂה שֶׁאִם לֹא רָצָה לְהִטָּמֵא מְטַמְּאִין אוֹתוֹ עַל כָּרְחוֹ. בַּמֶּה דְּבָרִים אֲמוּרִים בִּזְכָרִים שֶׁהֻזְהֲרוּ עַל הַטֻּמְאָה אֲבָל הַכֹּהֲנוֹת הוֹאִיל וְאֵינָן מֻזְהָרוֹת עַל הַטֻּמְאָה כֵּן אֵינָן מְצֻוּוֹת לְהִתְטַמֵּא לַקְּרוֹבִים. אֶלָּא אִם רָצוּ מִתְטַמְּאוֹת וְאִם לָאו לֹא מִטַּמְּאוֹת:
כסף משנה
6.
See how severe the mitzvah of mourning is! For the prohibition against ritual impurity is superseded so that a priest can tend to his relatives' burial and mourn for them, as Leviticus 21:2-3 states: "Except to one's flesh, to whom he is close, to his mother... to her shall he become impure." This is a positive commandment; if he does not desire to become impure, we force him to become impure against his will.
To whom does the above apply? To males who are commanded against contracting ritual impurity. Different rules apply to female members of the priestly family. Since they are not commanded against contracting ritual impurity, they are also not commanded to become impure when tending to their relatives' burial. If they desire, they may become impure and if not, they do not become impure.

הלכה ז
אִשְׁתּוֹ שֶׁל כֹּהֵן מִתְטַמֵּא לָהּ עַל כָּרְחוֹ. וְאֵינוֹ מִטַּמֵּא לָהּ אֶלָּא מִדִּבְרֵי סוֹפְרִים. עֲשָׂאוּהָ כְּמֵת מִצְוָה. כֵּיוָן שֶׁאֵין לָהּ יוֹרֵשׁ אֶלָּא הוּא לֹא תִּמְצָא מִי שֶׁיִּתְעַסֵּק בָּהּ. וְאֵינוֹ מִטַּמֵּא אֶלָּא לִנְשׂוּאָהּ בִּלְבַד אֲבָל הָאֲרוּסָה אֵינוֹ מִטַּמֵּא לָהּ:
כסף משנה
7.
A priest is forced to contract ritual impurity to tend to his deceased wife. This obligation is Rabbinic in origin. Our Sages had her considered as an unattended corpse. Since she has no other heir aside from him, there will be no one else to tend to her. He becomes impure only for a wife he has married. If he has merely consecrated her, he does not become impure for her.

הלכה ח
וְכֵן כָּל אוֹתָן שֶׁאָמְרוּ שֶׁאֵין מִתְאַבְּלִין עֲלֵיהֶן כְּגוֹן הֲרוּגֵי בֵּית דִּין וְשֶׁפָּרְשׁוּ מִדַּרְכֵי צִבּוּר וְהַנְּפָלִים וְהַמְאַבֵּד עַצְמוֹ לָדַעַת אֵין הַכֹּהֵן מִטַּמֵּא לָהֶן. וְעַד מָתַי מְצֻוֶּה לְהִתְטַמֵּא לִקְרוֹבָיו עַד שֶׁיִּסָּתֵם הַגּוֹלֵל. אֲבָל מֵאַחַר שֶׁנִּסְתַּם הַגּוֹלֵל הֲרֵי הֵן כִּשְׁאָר כָּל הַמֵּתִים שֶׁאִם נִטְמָא בָּהֶן לוֹקֶה:
כסף משנה
8.
Similarly, a priest does not become impure for any of those individuals for whom we do not mourn as stated above: e.g., those executed by the court, those who deviate from the ways of the community, stillborn infants, and those who commit suicide.
Until when does the mitzvah to become impure apply? Until the grave is covered. Once the grave is covered, however, the graves of one's close relatives are like those of any other corpse. If a priest becomes impure for their sake, he should be punished by lashes.

הלכה ט
אִשְׁתּוֹ הַפְּסוּלָה אֵינוֹ מִטַּמֵּא לָהּ. לְפִיכָךְ מִי שֶׁשָּׁמְעָה שְׁמוּעָה שֶׁמֵּת בַּעְלָהּ וְנִשֵּׂאת וּבָא בַּעְלָהּ. שְׁנֵיהֶן אֵין מִטַּמְּאִין לָהּ שֶׁהֲרֵי הִיא פְּסוּלָה לִשְׁנֵיהֶן. אֲבָל מִטַּמֵּא הוּא לְאִמּוֹ אַף עַל פִּי שֶׁהִיא חֲלָלָה. וְכֵן מִטַּמֵּא לִבְנוֹ וּלְבִתּוֹ וּלְאָחִיו וְלַאֲחוֹתוֹ אַף עַל פִּי שֶׁהֵן פְּסוּלִין. אֲפִלּוּ הָיוּ מַמְזֵרִים מִטַּמֵּא לָהֶן:
כסף משנה
9.
A priest should not become impure for the sake of a wife whom he is forbidden to marry. Therefore if a woman heard a report that her husband died and hence remarried, and then her first husband came, neither husband should become impure for her sake, for she is forbidden to remain married to either of them.
A priest may, however, become impure for the sake of his mother, even though she is a challalah and he may become impure for the sake of his son, his daughter, his brother and his sister even though they are of tarnished lineage. Even if they are illegitimate, he should become impure for their sake.

הלכה י
אֲחוֹתוֹ הַנְּשׂוּאָה אֵינוֹ מִטַּמֵּא לָהּ אַף עַל פִּי שֶׁהִיא נְשׂוּאָה לְכֹהֵן. שֶׁנֶּאֱמַר (ויקרא כא ג) "הַבְּתוּלָה הַקְּרוֹבָה אֵלָיו אֲשֶׁר לֹא הָיְתָה לְאִישׁ". הַבְּתוּלָה פְּרָט לַאֲנוּסָה וּמְפֻתָּה. יָכוֹל שֶׁאֲנִי מוֹצִיא אֶת הַבּוֹגֶרֶת וּמֻכַּת עֵץ תַּלְמוּד לוֹמַר אֲשֶׁר לֹא הָיְתָה לְאִישׁ מִי שֶׁהֲוָיָתָהּ בִּידֵי אִישׁ. אֲשֶׁר לֹא הָיְתָה לְאִישׁ פְּרָט לַאֲרוּסָה שֶׁאֵינוֹ מִטַּמֵּא לָהּ אַף עַל פִּי שֶׁהִיא אֲרוּסָה לְכֹהֵן:
כסף משנה
10.
When a priest's sister is married - even to another priest, he does not become impure for her sake, "as Leviticus 21:3 states: "his virgin sister who is close to him who has not been with a man." "Virgin" excludes a girl who has been raped or seduced. Should we also exclude a woman who attain majority or a woman who lost her signs of virginity because of reasons other than relations? The Torah teaches: "who has not been with a man," i.e., excluded is only one who lost her virginity because of a man. "Who has not been with a man" - this also excludes a sister who has been consecrated. He does not become impure, for her sake even if she is consecrated to a priest.

הלכה יא
נִתְגָּרְשָׁה אֲחוֹתוֹ מִן הָאֵרוּסִין מִטַּמֵּא לָהּ. שֶׁנֶּאֱמַר (ויקרא כא ג) "הַקְּרוֹבָה אֵלָיו" לְהָבִיא אֶת הַמְגֹרֶשֶׁת מִן הָאֵרוּסִין:
כסף משנה
11.
If, however, a priest's sister is divorced after consecration, before marriage, he must become impure for her sake. The phrase "who is close to him" includes a sister divorced after consecration.

הלכה יב
אָחִיו וַאֲחוֹתוֹ מֵאִמּוֹ אֵינוֹ מִטַּמֵּא לָהֶן. שֶׁנֶּאֱמַר (ויקרא כא ב) "וְלִבְנוֹ וּלְבִתּוֹ וּלְאָחִיו" (ויקרא כא ג) "וְלַאֲחֹתוֹ". מַה בְּנוֹ הָרָאוּי לִירֻשָּׁתוֹ אַף אָחִיו וַאֲחוֹתוֹ הָרְאוּיִים לִירֻשָּׁתוֹ:
כסף משנה
12.
A priest does not become impure for the sake of his maternal brother and sister, as implied by Leviticus 21:2-3: "To his son and to his daughter, to his brother and to his sister." Just as we are speaking of a son who is fit to inherit his father's estate; so, too, he must be fit to inherit the estates of his brother and sister.

הלכה יג
הַסְּפֵקוֹת אֵינוֹ מִטַּמֵּא לָהֶן שֶׁנֶּאֱמַר (ויקרא כא ג) "לָהּ יִטַּמָּא" מִטַּמֵּא הוּא עַל הַוַּדַּאי וְאֵינוֹ מִטַּמֵּא עַל הַסָּפֵק. לְפִיכָךְ הַוְּלָדוֹת שֶׁנִּתְעָרְבוּ וְהַבֵּן שֶׁהוּא סָפֵק בֶּן שִׁבְעָה לָאַחֲרוֹן אוֹ בֶּן תִּשְׁעָה לָרִאשׁוֹן וְכֵן כָּל כַּיּוֹצֵא בָּהֶן אֵינוֹ מִטַּמֵּא לָהֶן מִסָּפֵק. וְכֵן כָּל הַמִּתְגָּרֶשֶׁת סְפֵק גֵּרוּשִׁין אוֹ בְּגֵט פָּסוּל אֵינוֹ מִטַּמֵּא לָהּ:
כסף משנה
13.
A priest does not become impure for the sake of relatives whose family connection is doubtful, as implied by Leviticus 21:3: "to her shall he become impure." He becomes impure for those whose connection is definite and not for those whose connection is doubtful. Accordingly, in an instance where children become intermingled, there is a son concerning whom there is a question whether he was born after seven months from conception to his mother's later husband or after nine months to her first husband, and all the like, he does not become impure for their sake due to the doubt.
Similarly, in all cases concerning divorce that involve a question concerning the validity of the divorce or an invalid bill of divorce, , the priest does not become impure for the sake of his wife.

הלכה יד
אֵין הַכֹּהֵן מִטַּמֵּא לְאֵבֶר מִן הַחַי מֵאָבִיו וְלֹא לְעֶצֶם מֵעַצְמוֹת אָבִיו. וְכֵן הַמְלַקֵּט עַצְמוֹת אָבִיו אֵינוֹ מִטַּמֵּא לָהֶן אַף עַל פִּי שֶׁהַשִּׁדְרָה קַיֶּמֶת:
כסף משנה
14.
A priest may not become impure for the sake of a limb severed from his father while alive, nor for the sake of one of his father's bones. Similarly, when one's father's bones are being collected - even if his entire backbone is intact - a priest may not become impure for their sake.

הלכה טו
נִקְטַע רֹאשׁוֹ שֶׁל אָבִיו אֵינוֹ מִטַּמֵּא לוֹ שֶׁנֶּאֱמַר (ויקרא כא ב) "לְאָבִיו" בִּזְמַן שֶׁהוּא שָׁלֵם וְלֹא בִּזְמַן שֶׁהוּא חָסֵר. וְכֵן שְׁאָר הַקְּרוֹבִים. הַטֻּמְאָה לַקְּרוֹבִים דְּחוּיָה הִיא וְלֹא הֻתְּרָה לַכּל. 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:
כסף משנה
15.
If his father's head is decapitated, he may not become impure for his sake. This is implied by Leviticus 21:2: "To his father," i.e., at a time when his corpse is intact and not when it is impaired. Similar laws apply with regard to other relatives.
The prohibition against contact with ritual impurity is bypassed with regard to one's relatives; it is not released entirely. For this reason, a priest is forbidden to become impure for the sake of another corpse at the time he has become impure for the sake of his relatives. This is implied by Leviticus 21:3: "to her shall he become impure," i.e., to her alone. He does not become impure for the sake of others together with her. He should not say: "Since I became impure for the sake of my father, I will go gather so-and-so's bones" or "...touch so-and-so's grave."
Therefore when the relative of a priest dies, care must be taken to bury him at the edge of the cemetery, so that he will not have to enter the cemetery and become impure because of other graves when he buries his dead.

שופטים הלכות אבל פרק ב
Shoftim Eivel Chapter 2