רגל הוה וטומאת עם הארץ ברגל כטהרה שוינהו רבנן דכתיב (שופטים כ, יא) ויאסף כל איש ישראל אל העיר כאיש אחד חברים הכתוב עשאן כולן חברים
This incident occurred during a pilgrimage Festival, either Passover, Sukkot, or Shavuot, and the Sages rendered the ritual impurity of an am ha’aretz during a pilgrimage Festival as purity. As it is written: “And all the men of Israel gathered to the city, like one man, united [ḥaverim]” (Judges 20:11). Whenever all the Jewish people gather in a single place, such as on a pilgrimage Festival, the verse renders all of them ḥaverim, even one who is an am ha’aretz. There was therefore no concern for impurity due to the saliva of an am ha’aretz. Yet, the High Priest was concerned that this Sadducee was one who engages in intercourse with a menstruating woman.
מתני׳ דם עובדת כוכבים ודם טהרה של מצורעת ב"ש מטהרים ובית הלל אומרים כרוקה וכמימי רגליה
MISHNA: With regard to the blood of a menstruating gentile woman or a gentile zava, and the blood discharged by a female Jewish leper during the days of purity of a woman who gives birth, Beit Shammai deem them ritually pure, and Beit Hillel say: The halakhic status of the blood of the gentile woman is like that of her saliva and her urine, which impart impurity only while moist. Likewise, the blood discharged by a Jewish leper during the days of purity imparts impurity only when moist.
דם היולדת שלא טבלה ב"ש אומרים כרוקה וכמימי רגליה וב"ה אומרים מטמא לח ויבש
With regard to the blood of a woman who gave birth and reached the conclusion of her days of impurity, i.e., seven days after giving birth to a male or fourteen days after giving birth to a female, but who did not yet immerse in a ritual bath, Beit Shammai say: Although she has yet to immerse in a ritual bath, the blood does not retain the halakhic status of menstrual blood. Rather, the status of the blood is like that of her saliva and her urine, and it imparts impurity only while moist. And Beit Hillel say: Since she did not immerse in a ritual bath, her blood is considered like that of a menstruating woman, and it imparts impurity whether it is moist or dry.
ומודים ביולדת בזוב שהיא מטמאה לח ויבש
And Beit Shammai concede to Beit Hillel in the case of a woman who gives birth as a zava, where the woman must count seven clean days from the conclusion of her days of impurity, that any blood she sees during those seven days imparts impurity whether it is moist or dry.
גמ׳ ולית להו לב"ש (ויקרא טו, ב) דבר אל בני ישראל ואמרת אליהם איש איש כי יהיה זב בני ישראל מטמאין בזיבה ואין העובדי כוכבים מטמאין בזיבה אבל גזרו עליהן שיהו כזבין לכל דבריהם
GEMARA: The mishna teaches that according to Beit Shammai the blood of a gentile woman does not impart impurity. The Gemara objects: And do Beit Shammai not accept that which is taught with regard to the verse: “Speak to the children of Israel and say to them, when any man has an issue [zav] out of his flesh, his issue is impure” (Leviticus 15:2), from which it is inferred: By Torah law, the children of Israel become impure through ziva and gentiles do not become impure through ziva, but the Sages decreed concerning them that they shall be like zavin in all their matters of ritual purity.
אמרי לך ב"ש (ההוא בזכרים איתמר דאי בנקבות) היכי לעביד ליטמא לח ויבש עשיתו כשל תורה ליטמי לח ולא ליטמי יבש חלקת בשל תורה
The Gemara responds: Beit Shammai could say to you that this was stated only with regard to males, not females. As, if it was stated even with regard to females, how should one act with regard to this impurity? Should their blood impart impurity whether it is moist or dry? If so, you have rendered it like blood that imparts impurity by Torah law, and people will mistakenly come to burn teruma that comes into contact with it. Perhaps one will suggest that it should impart impurity only while it is moist and it should not impart impurity when it is dry. But if so, you will have differentiated between moist and dry blood even with regard to blood that is impure by Torah law, i.e., one might mistakenly conclude that the blood of Jewish women imparts impurity only when it is moist, when in fact it imparts impurity whether it is moist or dry.
אי הכי רוקה ומימי רגליה נמי כיון דעבדינן היכרא בדמה מידע ידיע דרוקה ומימי רגליה דרבנן
The Gemara objects: If so, then with regard to the saliva and urine of a gentile zava, which impart impurity by rabbinic law only when moist, Beit Shammai should also rule that they do not impart impurity at all, in order to distinguish their saliva and urine from that of a Jewish zava, which by Torah law impart impurity only when moist (see 54b). The Gemara responds: Since we implement a conspicuous marker with regard to the blood of a gentile woman, i.e., it is clear that her status is different from that of a Jewish woman in that her blood does not impart impurity whatsoever, everyone will know that the impurity of her saliva and her urine is only by rabbinic law, and there is no concern that people might come to mistakenly burn teruma that comes into contact with the saliva and urine of a gentile zava.
ולעביד היכרא ברוקה ומימי רגליה ולטמויי לדמה רוקה ומימי רגליה דשכיחי גזרו בהו רבנן דמה דלא שכיחא לא גזרו ביה רבנן
The Gemara persists: And let them implement a conspicuous marker with regard to the saliva and urine of a gentile woman, that they should not impart impurity whatsoever, and let them deem her blood impure even when dry. In this manner, everyone will know that the impurity of a gentile woman applies only by rabbinic law, and they will not come to treat that which is impure by Torah law in the same manner. The Gemara responds: With regard to her saliva and her urine, which are relatively common, the Sages decreed that they are impure, but with regard to her blood, which is not as common, the Sages did not decree that it is impure.
אמר רבא זובו טמא אפילו לב"ש קריו טהור אפילו לב"ה
§ With regard to a gentile man, Rava says: The ziva of a gentile man is ritually impure, even according to the opinion of Beit Shammai, who maintain that the ziva of a gentile woman does not impart impurity whatsoever. By contrast, the semen of a gentile is pure, even according to the opinion of Beit Hillel, who hold that the blood of menstruating gentiles and the blood of their ziva imparts impurity when it is moist.
זובו טמא אפילו לב"ש דהא איכא למעבד היכרא בקריו
Rava elaborates: The ziva of a gentile man is impure, even according to the opinion of Beit Shammai, as it is possible to implement a conspicuous marker with his semen, i.e., since his semen does not impart impurity whatsoever, everyone will know that the impurity imparted by the ziva of a gentile applies by rabbinic law, and they will not come to burn teruma that comes in contact with the ziva of a gentile.
קריו טהור אפי' לב"ה עבוד ביה רבנן היכרא כי היכי דלא לשרוף עליה תרומה וקדשים
And the semen of a gentile is ritually pure, even according to the opinion of Beit Hillel. This is because the Sages had to implement a conspicuous marker with regard to it to indicate that the ziva of a gentile imparts impurity only by rabbinic law in order that they will not come to burn teruma and consecrated items that come into contact with their ziva, as must be performed with teruma and consecrated items that contract impurity by Torah law.
ולעביד היכרא בזובו ולטמויי לקריו זובו דלא תלי במעשה גזרו ביה רבנן קריו דתלי במעשה לא גזרו ביה רבנן
The Gemara objects: And let the Sages implement a conspicuous marker with regard to the ziva of a gentile man, that it should not impart impurity whatsoever, and let them deem his semen impure. The Gemara explains: With regard to his ziva, which is not dependent on an action he performs but is emitted on its own, the Sages decreed that it is impure; with regard to his semen, which is dependent on an action he performs, the Sages did not decree that it is impure.
לימא מסייע ליה עובדת כוכבים שפלטה שכבת זרע מישראל טמאה ובת ישראל שפלטה שכבת זרע מן העובד כוכבי' טהורה מאי לאו טהורה גמורה לא טהורה מדאורייתא טמאה מדרבנן
The Gemara suggests: Let us say that the following mishna (Mikvaot 8:4) supports Rava’s opinion: In the case of a gentile woman who discharged semen that came from a Jew who engaged in intercourse with her, the semen is impure, as it came from a Jew. And in the case of a Jewish woman who discharged semen that came from a gentile, the semen is pure. What, is it not correct to say that the mishna means the semen of the gentile is entirely pure, in accordance with the opinion of Rava? The Gemara refutes this suggestion: No, perhaps the mishna means that the semen of a gentile is pure by Torah law but impure by rabbinic law, whereas according to Rava, the semen of a gentile is pure even by rabbinic law.
ת"ש נמצאת אומר שכבת זרע של ישראל טמאה בכל מקום
The Gemara cites another source that possibly supports Rava’s opinion: Come and hear a baraita: You are found to say the semen of a Jew is impure wherever it is found,