רַבִּי יוֹחָנָן הֲוָה רְגִיל דַּהֲוָה קָא אָזֵיל וְיָתֵיב אַשַּׁעֲרֵי דִטְבִילָה. אֲמַר: כִּי סָלְקָן בְּנוֹת יִשְׂרָאֵל וְאָתְיָין מִטְּבִילָה, מִסְתַּכְּלָן בִּי, וְנֶהֱוֵי לְהוּ זַרְעָא דְּשַׁפִּירֵי כְּווֹתִי
Rabbi Yochanan would go and sit by the entrance to the ritual bath. He said to himself: When Jewish women come up from their immersion [after their menstruation,] they should see me first so that they have beautiful children like me
(ד) כָּל הַיַּמִּים כְּמִקְוֶה, שֶׁנֶּאֱמַר (בראשית א), וּלְמִקְוֵה הַמַּיִם קָרָא יַמִּים, דִּבְרֵי רַבִּי מֵאִיר. רַבִּי יְהוּדָה אוֹמֵר, הַיָּם הַגָּדוֹל כְּמִקְוֶה. לֹא נֶאֱמַר יַמִּים, אֶלָּא שֶׁיֶּשׁ בּוֹ מִינֵי יַמִּים הַרְבֵּה. רַבִּי יוֹסֵי אוֹמֵר, כָּל הַיַּמִּים מְטַהֲרִים בְּזוֹחֲלִין, וּפְסוּלִין לַזָּבִין וְלַמְצֹרָעִים, וּלְקַדֵּשׁ מֵהֶם מֵי חַטָּאת:
(4) All the seas are like a mikveh, as the verse says (Genesis 1:10) "And the gathering [literally: mikveh] of water, God called seas," according to Rabbi Meir. Rabbi Yehuda says: the great sea [i.e. the Mediterranean, alone] is like a mikveh; the verse only says "seas" [in the plural] because it contains many types of seas.
(א) דִין תּוֹרָה שֶׁכָּל מַיִם מְכֻנָּסִין טוֹבְלִין בָּהֶן שֶׁנֶּאֱמַר (ויקרא יא לו) "מִקְוֵה מַיִם" מִכָּל מָקוֹם. וְהוּא שֶׁיִּהְיֶה בָּהֶן כְּדֵי לְהַעֲלוֹת בָּהֶן כְּדֵי טְבִילָה לְכָל גּוּף הָאָדָם בְּבַת אַחַת. שִׁעֲרוּ חֲכָמִים אַמָּה עַל אַמָּה בְּרוּם שָׁלֹשׁ אַמּוֹת. וְשִׁעוּר זֶה הוּא מַחֲזִיק אַרְבָּעִים סְאָה מַיִם בֵּין שְׁאוּבִין בֵּין שֶׁאֵינָן שְׁאוּבִין:
(1) According to biblical law, any water that is gathered may be used for immersion, as it is written: "A gathering of water" (Leviticus 11:36), of any kind; provided that there is enough of it to fill up the measure required for the complete immersion of a human's entire body. The sages have calculated the measure to be one cubit square by three cubits deep. This quantity holds forty seahs (sixty gallons) water, whether drawn or undrawn [from any kind of receptacle].
Rabbi Ḥiyya bar Ashi said above that Rav said that the laws governing interpositions that invalidate ritual immersion are halakhot transmitted to Moses from Sinai. The Gemara challenges this assertion: These, too, are written in the Torah, as it is written: “And he shall bathe all his flesh in the water” (Leviticus 15:16), and the Sages derived that nothing should intervene between flesh and the water. The definite article in the phrase “in the water” indicates that this bathing is performed in water mentioned elsewhere, i.e., specifically in the water of a ritual bath, and not in just any water. And the phrase “all his flesh” indicates that it must be in water into which all of the body can enter, i.e., in which a person can immerse their entire body at once. And how much water is that? It is a cubit by a cubit by the height of three cubits. And the Sages calculated the volume of a ritual bath of this size and determined that the waters of a ritual bath measure forty se’a.
(ט) הָאוֹמֵר, אֶחֱטָא וְאָשׁוּב, אֶחֱטָא וְאָשׁוּב, אֵין מַסְפִּיקִין בְּיָדוֹ לַעֲשׂוֹת תְּשׁוּבָה. אֶחֱטָא וְיוֹם הַכִּפּוּרִים מְכַפֵּר, אֵין יוֹם הַכִּפּוּרִים מְכַפֵּר. עֲבֵרוֹת שֶׁבֵּין אָדָם לַמָּקוֹם, יוֹם הַכִּפּוּרִים מְכַפֵּר. עֲבֵרוֹת שֶׁבֵּין אָדָם לַחֲבֵרוֹ, אֵין יוֹם הַכִּפּוּרִים מְכַפֵּר, עַד שֶׁיְּרַצֶּה אֶת חֲבֵרוֹ. אֶת זוֹ דָּרַשׁ רַבִּי אֶלְעָזָר בֶּן עֲזַרְיָה, מִכֹּל חַטֹּאתֵיכֶם לִפְנֵי ה' תִּטְהָרוּ (ויקרא טז), עֲבֵרוֹת שֶׁבֵּין אָדָם לַמָּקוֹם, יוֹם הַכִּפּוּרִים מְכַפֵּר. עֲבֵרוֹת שֶׁבֵּין אָדָם לַחֲבֵרוֹ, אֵין יוֹם הַכִּפּוּרִים מְכַפֵּר, עַד שֶׁיְּרַצֶּה אֶת חֲבֵרוֹ. אָמַר רַבִּי עֲקִיבָא, אַשְׁרֵיכֶם יִשְׂרָאֵל, לִפְנֵי מִי אַתֶּם מִטַּהֲרִין, וּמִי מְטַהֵר אֶתְכֶם, אֲבִיכֶם שֶׁבַּשָּׁמַיִם, שֶׁנֶּאֱמַר (יחזקאל לו), וְזָרַקְתִּי עֲלֵיכֶם מַיִם טְהוֹרִים וּטְהַרְתֶּם. וְאוֹמֵר (ירמיה יז), מִקְוֵה יִשְׂרָאֵל ה', מַה מִּקְוֶה מְטַהֵר אֶת הַטְּמֵאִים, אַף הַקָּדוֹשׁ בָּרוּךְ הוּא מְטַהֵר אֶת יִשְׂרָאֵל:
(9) One who says, "I will sin, and then repent, I will sin again, and then repent," will not receive an opportunity to repent; for one who says "I will sin, and Yom Kipur will atone," Yom Kippur will not atone. Yom Kippur atones for transgressions between a person and God, but for a transgression against one's neighbor, Yom Kipur cannot atone, until they appeases their neighbor.
Thus R. Eleazar ben Azariah expounds the text, "From all your sins before God shall you be clean": For transgressions between a person and God, Yom Kippur atones, for transgressions against one's neighbor, Yom Kippur cannot atone, until they appease their neighbor. R. Akiva says, Happy are you, Israel! Before whom are you purified, and who purifies you of your transgressions? God. For it is said, "Then will I sprinkle clean water upon you, and ye shall be clean"; and it is also said, "The ritual bath [lit. Hope] of Israel is the God"; even as a ritual bath purifies the unclean, so does the Holy One, Blessed Be, purify Israel.
- Either gender
- As part of a conversion to Judaism
- Immersion of utensils acquired from a gentile
- By a bridegroom, on the day of his wedding
- By a father, prior to the circumcision of his son
- By a kohen prior to a service in which he will recite the priestly blessing
- Before Yom Kippur
- Before a Jewish holiday
- Weekly before Shabbat, under Hasidic and Haredi customs
- Every day, under Hasidic customs
- after Keri — normal emissions of semen, whether from sexual activity, or from nocturnal emission. Bathing in a mikveh due to Keri is required by the Torah in order that one should be allowed to consume from a heave offering or sacrifice; while Ezra instituted that one should also do so in order to be allowed to recite words of Torah. The latter case is known as tevilath Ezra ("the immersion of Ezra")
- after Zav/Zavah — abnormal discharges of body fluids
- after Tzaraath — certain skin condition(s). These are termed lepra in the Septuagint, and therefore traditionally translated into English as leprosy; this is probably a translation error, as the Greek term lepra mostly refers to psoriasis, and the Greek term for leprosy was elephas or elephantiasis.
- by anyone who came into contact with someone suffering from Zav/Zavah, or into contact with someone still in Niddah (normal menstruation), or who comes into contact with articles that have been used or sat upon by such persons
- by a Kohen who is being consecrated
- by the Kohen Gadol on Yom Kippur, after sending away the goat to Azazel, and by the man who leads away the goat
- by the Kohen who performed the Red Heifer ritual
- after contact with a corpse or grave, in addition to having the ashes of the Red heifer ritual sprinkled upon them
- after eating meat from an animal that died naturally