הַבָּא רֹאשׁוֹ וְרֻבּוֹ בְּמַיִם שְׁאוּבִין אוֹ שֶׁנָּפְלוּ עַל רֹאשׁוֹ וְעַל רֻבּוֹ שְׁלֹשָׁה לוֹגִין מַיִם שְׁאוּבִין הֲרֵי הוּא כְּשֵׁנִי לְטֻמְאָה עַד שֶׁיִּטְבּל. וְאִם נָגַע בָּאֳכָלִין עֲשָׂאָן שְׁלִישִׁי. וְאִם נָגַע בְּמַשְׁקִין טְמֵאִים עֲשָׂאָן תְּחִלָּה לְטַמֵּא אֳכָלִים וּמַשְׁקִין אֲחֵרִים אֲבָל לֹא לְטַמֵּא כֵּלִים. וּמִפְּנֵי מָה גָּזְרוּ טֻמְאָה עַל אָדָם זֶה. מִפְּנֵי שֶׁהָיוּ טְבוּלֵי יוֹם טוֹבְלִין בִּמְעָרוֹת שֶׁמֵּימֵיהֶן רָעִים וְאַחַר כָּךְ הָיוּ רוֹחֲצִין בְּמַיִם שְׁאוּבִים יָפִים דֶּרֶךְ נְקִיּוּת וּפָשַׁט הַמִּנְהָג כָּךְ עַד שֶׁהָיוּ רֹב הָעָם מְדַמִּים שֶׁמַּיִם שְׁאוּבִים שֶׁרוֹחֲצִין בָּהֶן בָּאַחֲרוֹנָה הֵן שֶׁמְּטַהֲרִין לֹא הַטְּבִילָה שֶׁבְּמֵי מִקְוֶה וְהָיוּ טוֹבְלִין בְּזִלְזוּל בְּלֹא כַּוָּנָה. וּלְפִיכָךְ גָּזְרוּ שֶׁכָּל שֶׁבָּא רֹאשׁוֹ וְרֻבּוֹ בְּמַיִם שְׁאוּבִים אוֹ שֶׁנָּפְלוּ עַל רֹאשׁוֹ וְרֻבּוֹ נִטְמָא וְנַעֲשָׂה כְּשֵׁנִי לְטֻמְאָה. אֲפִלּוּ טָהוֹר שֶׁאֵינוֹ טְבוּל יוֹם אִם נָפְלוּ עַל רֹאשׁוֹ וְרֻבּוֹ שְׁלֹשָׁה לוֹגִין מַיִם שְׁאוּבִין אוֹ שֶׁבָּא רֹאשׁוֹ וְרֻבּוֹ בְּמַיִם שְׁאוּבִין הֲרֵי זֶה כְּשֵׁנִי לְטֻמְאָה עַד שֶׁיִּטְבּל. טָבַל אֵינוֹ צָרִיךְ הַעֲרֵב שֶׁמֶשׁ מִפְּנֵי שֶׁעִקַּר טֻמְאָה זוֹ מִדִּבְרֵיהֶן. וְכֵן הָאוֹכֵל אֳכָלִין טְמֵאִים וְהַשּׁוֹתֶה מַשְׁקִין טְמֵאִין וְטָבַל אֵינוֹ צָרִיךְ הַעֲרֵב שֶׁמֶשׁ. וְכֵן כֵּלִים שֶׁנִּטְמְאוּ בְּמַשְׁקִין כֵּיוָן שֶׁמַּטְבִּילָן טִהֲרוּ וְאֵין צְרִיכִין הַעֲרֵב שֶׁמֶשׁ מִפְּנֵי שֶׁטֻּמְאוֹת אֵלּוּ עִקָּרָן מִדִּבְרֵיהֶן:
When a person immerses his head and the majority of his body in drawn water or three lugim of drawn water fall on his head and the majority of his body, he is a secondary derivative of impurity until he immerses himself in a mikveh. If he touches foods, he causes them to be considered as a tertiary derivative. If he touches liquids, he imparts impurity to them, causing them to be considered as a primary derivative and they impart impurity to other foods and liquids. They do not, however, impart impurity to keilim. Why did the Sages decree that such a person should be impure? Because people would immerse in caves where the water was foul and then they would wash with fresh drawn water for the sake of cleanliness. This became such a widespread practice that the majority of people got the impression that the drawn water in which the people would ultimately wash was the agent that conveyed ritual purity and not the immersion in the waters of the mikveh. Therefore, they would immerse themselves carelessly, without attention to details. Accordingly, our Sages decreed that when a person immerses his head and the majority of his body in drawn water or three lugim of drawn water fall on his head and the majority of his body, he becomes a secondary derivative of impurity. Even when three lugim of drawn water falls on the head and the majority of the body of a person who was pure or he immerses his head and the majority of his body in drawn water, he becomes a secondary derivative of impurity until he immerses himself. After a person who contracted impurity in such a manner immerses himself, he need not wait until nightfall to regain purity, for the impurity contracted by this person is fundamentally a Rabbinic decree. Similarly, a person who contracted impurity because he ate impure foods or drank impure liquids and then immersed himself need not wait until nightfall to regain purity. Similarly, when keilim become impure due to contact with impure liquids, once they were immersed, they become pure. There is no need to wait until nightfall, because these impurities are fundamentally Rabbinic decrees.
