Chapter 40, Section 3 (פֶּרֶק מ׳ אוֹת ג׳)

3. Rabbi Yishma’el said: thus said Rabbi Akiva in the name of Rabbi Eliezer the Great (ג. אָמַר רַבִּי יִשְׁמָעֵאל: כָּךְ אָמַר רַבִּי עֲקִיבָא מִשּׁוּם רַבִּי אֱלִיעֶזֶר הַגָּדוֹל): one who purifies himself for the mystery of Torah (הַמְזַקֵּק עַצְמוֹ בְּסוֹד תּוֹרָה), he shall wash his garments and his clothing (יְכַבֵּס בְּגָדָיו וּשְׂמְלֹתָיו), and he shall ascend with stringent immersion (וְיַעֲלֶה טְבִילָה חֲמוּרָה), on account of doubtful separation due to seminal emission (מִסָּפֵק חוֹצֵץ קֶרִי). And he shall sit twelve days in a room or an upper chamber (וְיֵשֵׁב שְׁנֵים עָשָׂר יוֹם בַּחֶדֶר אוֹ בַּעֲלִיָּה), he shall not go out and he shall not come in (אַל יֵצֵא וְאַל יָבוֹא), and he shall not eat and he shall not drink (וְאַל יֹאכַל וְאַל יִשְׁתֶּה), except from evening to evening he shall eat his bread—clean bread (אֶלָּא מֵעֶרֶב עַד עֶרֶב שֶׁיֹּאכַל לַחְמוֹ לֶחֶם נָקִי), and he shall drink water (וְיִשְׁתֶּה מַיִם), and he shall not taste of any kind of herb (וְאַל יִטְעַם כָּל מִינֵי יָרָק).