As we mentioned above, the Torah declares semen impure. Ezra the Scribe and his court extended this, ordaining that any man who had sexual relations or otherwise ejaculated semen may not pray or study Torah until immersing in a mikveh (BK 82b according to Rosh). The reason is that Torah must be studied with “awe, fear, trembling, and trepidation,” just as we received it at Sinai, whereas semen is ejaculated “out of frivolity and arrogance” (Berakhot 22a and Rashi ad loc.). Another reason is “so that Jews are not like roosters, which mate, get right up, and go eat” (y. Berakhot 3:4), or “so that Torah scholars do not constantly cohabit with their wives, like roosters” (Berakhot 22a).
According to all of these reasons, Ezra’s ordinance does not indicate that there is something wrong with sexual intimacy between husband and wife. Rather, they should not overindulge as does a rooster, which has nothing else to live for. Human beings have other purposes, spiritual as well as professional. If people spent all their time mating like roosters, they would not manage to fill all their other roles. The requirement of immersion creates a certain inconvenience whose purpose is to ensure that people fulfill the mitzva of ona with the appropriate frequency and not to excess.
Additionally, immersion is meant to separate between the different realms of a person’s life. Torah must be studied with the appropriate gravitas, with a sense of fear and awe, whereas the mitzva of ona is fulfilled with a spirit of playfulness, liberation, and unbounded joy, as it is written: “Yitzḥak was being playful with Rivka his wife” (Bereishit 26:8). Rashi explains that “being playful” is a euphemism for sexual relations. This is similar to the Sages’ ordinance that men wear belts while they are speaking holy words, to separate the heart from the genitals, lest the urges emanating from the genitalia confound the head and heart and make it difficult to engage in spiritual matters with the requisite purity. Ultimately, the mind and emotions can become enslaved to the realization of lustful fantasies.
Therefore, in order to fortify his spiritual world, one must study Torah with awe, fear, trembling, and trepidation, as is becoming of its sanctity and seriousness. Then, when he later returns to physicality, he will be able to direct it properly. This explains why the Sages instituted a blessing to be recited upon putting on a belt in the morning: “Who girds Israel with strength” (Ozer Yisrael bi-gevura). The strength to separate between the heart and the genitals liberates a person from being enslaved by his urges and enables him to sanctify them through the mitzva of ona.
In practice, Ezra’s ordinance did not become widespread. Some people did not want to stop studying Torah, and since they found it inconvenient to immerse, they simply refrained from sexual relations, thereby forgoing both the mitzva of ona and the mitzva of procreation. In contrast, some others were happy to fulfill the mitzva of ona, but because of the inconvenience of immersion, they simply refrained from Torah study. Many others simply ignored the ordinance, wishing neither to detract from the mitzva of ona nor to lessen their Torah study. When the Sages saw that Ezra’s enactment was not accepted by the Jewish people, they rescinded it and permitted those who had ejaculated or had sexual relations to pray and study Torah without restriction (Berakhot 22a; MT, Laws of Reciting Shema 4:8). Nevertheless, some people are meticulous about immersing before studying Torah or praying, in accordance with Ezra’s ordinance. Others show their meticulousness by washing in nine kabin (approximately 11 liters) of water. Nowadays, when every home has a shower, it is good to be meticulous about this.
What is the actual procedure for washing in nine kabin? The water must be poured onto the person; he should not immerse in it (Berakhot 22a). The pouring must be continuous, without pause (MB 88:4). According to Raavad, the water must also be poured manually, so that all the water touches the body. According to this view, it seems that a shower would not be acceptable. However, Sefer Ḥasidim (§828) states that a person may fulfill the obligation even with water flowing on its own, as long as the water makes contact with his whole body, including his arms. Accordingly, taking a shower would be acceptable. Kaf Ha-ḥayim 88:7 and Yaskil Avdi 5, OḤ 13, agree. This is also the opinion of almost all the poskim, as cited in Yalkut Yosef 88:1 and Piskei Teshuvot 88:42. Some insist that the water must make contact with all parts of the body (Pri Megadim, Mishbetzot Zahav 88:1). Based on this, some advise first pouring water on the soles of the feet, because otherwise the poured water will not reach there (Kaf Ha-ḥayim 88:7). Others disagree, maintaining that a ḥatzitza (barrier) does not disqualify the nine kabin, as earlier authorities do not specify that a person must lift his feet from the floor (Responsa Ma’amar Mordechai §1-2, as cited in Sha’arei Teshuva 88:1). This implies that even those who insist that there must be no ḥatzitza, and that the soles of the feet must get wet, are not careful that the water touch every single part of the body, even inside the ears. If they had meant to be that stringent, they would have needed to say so explicitly. Furthermore, nine kabin of water is a relatively small amount, too small to make contact with every single part of a person’s body. R. Ephraim Zalman Margolies implies this in Mateh Ephraim 606:10, and he writes it explicitly in Elef Le-mateh 606:3; see also Piskei Teshuvot 88:5.
Ma’amar Mordechai 88:2 understands Rambam and SA to mean that the ordinance was limited to Torah scholars, who study Torah frequently. Today, though, when it is easy to follow the ordinance and it also fits in easily with our hygienic lifestyle, it is best for everyone to follow it.