in each, as if its time passed, it is void, unlike the mitzva of circumcision, which can be fulfilled at a later date if the child is not circumcised on the eighth day. Rather, this is the reason for the opinion of Rabbi Eliezer, as the verse says: ''And on the eighth day the flesh of his foreskin shall be circumcised'' (Leviticus 12:3), indicating that he is circumcised on the eighth day even if it falls on Shabbat.

The Gemara asks: And let the Torah write this principle only with regard to the mitzva of circumcision, and let these other mitzvot come and derive their halakhot from it. The Gemara answers: Because this suggestion can be refuted: What is unique about the mitzva of circumcision? That thirteen covenants were established over it, as the word covenant is mentioned thirteen times in the passage dealing with the circumcision of Abraham (Genesis 17). Owing to its great significance, other mitzvot cannot be derived from it.

The Gemara departs from the facilitators of circumcision to the halakha of circumcision itself and asks: The Rabbis only disagree with Rabbi Eliezer with regard to actions that facilitate circumcision, which, in their view, do not override Shabbat; however, with regard to circumcision itself, everyone agrees that it overrides Shabbat. From where do we derive this halakha? Ulla said: This is a halakha transmitted to Moses from Sinai, but there is no biblical basis for it. And so too, Rabbi Yitzḥak said: It is a halakha transmitted to Moses from Sinai.

The Gemara raises an objection from that which was taught in the Tosefta: From where is it derived that saving a life overrides Shabbat? Rabbi Elazar ben Azarya says it is derived from the mitzva of circumcision: Just as circumcision, which pertains to only one of a person’s limbs, overrides Shabbat, all the more so it is an a fortiori inference that saving a life, which is a mitzva that pertains to the entire person, overrides Shabbat.

And if it should enter your mind to say that circumcision may be performed on Shabbat based on a halakha transmitted to Moses from Sinai, is an a fortiori inference derived from a halakha transmitted to Moses from Sinai? Wasn’t it taught explicitly in a baraita that an a fortiori inference cannot be derived from a halakha transmitted to Moses from Sinai? Rabbi Akiva sought to derive that a nazirite who comes into contact with a quarter log of blood from a corpse becomes ritually impure and is required to shave his hair. He sought to do this based on an a fortiori inference from the halakha of the bone from a dead person the size of a grain of barley, as he had a received tradition that a nazirite is required to shave his hair due to that contact. Rabbi Elazar ben Azarya said to him: Akiva, the halakha that a bone the size of a grain of barley transmits ritual impurity is a halakha transmitted to Moses from Sinai, and you would derive from it that a quarter of a log of blood transmits ritual impurity based upon an a fortiori inference, and one does not derive an a fortiori inference from a halakha transmitted to Moses from Sinai. The Tosefta explicitly states that Rabbi Elazar ben Azarya himself derived an a fortiori inference from the halakha of circumcision on Shabbat. Clearly, then, it is derived from the Torah itself and not from a halakha transmitted to Moses from Sinai.

Rather, Rabbi Elazar said: This halakha is derived by means of a verbal analogy between the word sign that appears with regard to circumcision: ''And you shall be circumcised in the flesh of your foreskin; and it shall be a sign of the covenant between Me and you'' (Genesis 17:11), and sign that appears with regard to Shabbat: ''However, you shall keep My Shabbatot, for it is a sign between Me and you throughout your generations'' (Exodus 31:13). From this verbal analogy, it is derived that circumcision, which is a sign, may be performed even on Shabbat, which is itself a sign.

The Gemara asks: But if what you say is so, phylacteries, with regard to which the term sign is also written: ''And it shall be for a sign on your hand and for frontlets between your eyes'' (Exodus 13:16), should also override Shabbat, and they should be donned on that day.

Rather, this principle is derived by means of a different verbal analogy from the word covenant that appears with regard to circumcision: ''And you shall be circumcised in the flesh of your foreskin; and it shall be a sign of the covenant between Me and you'' (Genesis 17:11), and the word covenant that appears with regard to Shabbat: ''The children of Israel shall keep the Shabbat, to observe the Shabbat throughout their generations for a perpetual covenant'' (Exodus 31:16).

The Gemara raises a difficulty: If this is so, then the circumcision of an adult should also be permitted on Shabbat and it should not be limited to a child on the eighth day, as the term covenant is written with regard to him as well, as it applies to any Jewish male not yet circumcised. Therefore, let his circumcision override Shabbat. The halakha, however, is that only circumcision at its proper time on the eighth day overrides Shabbat.

Rather, this halakha is derived by means of a verbal analogy between the word generations that appears with regard to Shabbat: ''Throughout their generations for a perpetual covenant'' (Exodus 31:16), and the word generations that appears with regard to circumcision: ''And I shall establish My covenant between Me and you, and between your seed after you throughout their generations, for an everlasting covenant'' (Genesis 17:7).

The Gemara asks: If so, let ritual fringes too, with regard to which the term generations is also written, override Shabbat, and it should be permitted to affix ritual fringes to a garment on Shabbat.

Rather, Rav Naḥman bar Yitzḥak said: This halakha is derived not from one common word alone, but one derives it based upon the three words sign, covenant, and generations that appear with regard to circumcision, from sign, covenant, and generations that appear with regard to Shabbat, to the exclusion of these, i.e., ritual fringes and phylacteries, that with regard to each of them, one of these is written but not all three words together.

And Rabbi Yoḥanan said: The verse says: ''And on the eighth day…shall be circumcised'' (Leviticus 12:3), which means that the child is circumcised on the eighth day whenever it occurs, even on Shabbat.

Reish Lakish said to Rabbi Yoḥanan: But if what you say is so, then, with regard to those lacking atonement, such as a zav or a healed leper, who must after their immersion still bring an atonement offering in order to complete their purification process, with regard to whom the term on the day is also written, as in the verse: ''And on the eighth day he shall take two he-lambs without blemish, and one ewe-lamb of the first year without blemish'' (Leviticus 14:10), sacrificing their atonement offerings should also override Shabbat. Rabbi Yoḥanan responded: That verse is necessary to teach that the sacrifice must be brought during the day and not at night.

Reish Lakish asked: This verse with regard to the mitzva of circumcision is also necessary to teach that circumcision must be performed during the day and not at night. Rabbi Yoḥanan replied: That is derived from a different verse, which states: ''And he that is eight days old shall be circumcised among you throughout your generations'' (Genesis 17:12). That circumcision must take place during the day is derived from that verse.

Reish Lakish says: That matter, that the atonement offering must be sacrificed during the day, can also be derived from a different verse, as it is stated: ''This is the law of the burnt-offering, of the meal-offering, and of the sin-offering, and of the guilt-offering, and of the consecration-offering, and of the sacrifice of the peace-offerings; which the Lord commanded Moses at Mount Sinai on the day He commanded the children of Israel to present their offerings to the Lord in the wilderness of Sinai'' (Leviticus 7:37–38), and from here it is derived that all offerings are sacrificed by day and not at night.

The Gemara answers: Although this halakha is derived from: ''On the day He commanded,'' an additional source is necessary for those lacking atonement. It might have entered your mind to say that since the Torah shows him mercy by allowing him to bring an offering of poverty, as if one cannot afford to sacrifice the regular atonement offering, the Torah enables him to sacrifice a less costly one, let him also bring it at night, as perhaps the Torah shows him mercy and allows him to hasten his atonement. Therefore, it teaches us that he too must bring his offering only by day and not at night.

Ravina strongly objects to this reasoning: But if what you say is so, that the Torah has compassion on a person lacking atonement and is lenient with regard to the halakhot of the atonement offering, a non-priest should be fit to sacrifice them, and similarly, a priest who is an acute mourner, i.e., one whose relative died that same day and has not yet been buried, should be fit to sacrifice them. The Gemara answers: The verse has restored this. The additional verse that teaches that even one lacking atonement must sacrifice during the day, also teaches that the Torah was lenient with regard to this offering only in the ways explicitly stated in the Torah.

Rav Aḥa bar Ya’akov said: There is a different proof from the Torah that circumcision is performed even on Shabbat, for the verse said: ''On the eighth day,'' underscoring that circumcision is performed specifically on the eighth day and indicating that it is performed even on Shabbat.

The Gemara raises a difficulty: This usage of the term eighth is necessary to exclude the seventh day, i.e., a child may not be circumcised before the eighth day. The Gemara answers: The fact that one may not circumcise on the seventh day is derived from a different verse, as it is stated: ''And he that is eight days old shall be circumcised among you throughout your generations'' (Genesis 17:12).

The Gemara raises a further difficulty: Both verses are still necessary, one to exclude the seventh day and one to exclude the ninth day. As if it were derived from one verse alone, I would have said: It is on the seventh day that one may not circumcise, since the time to circumcise this child has not yet arrived and the obligation of circumcision is not yet in effect; however, from the eighth day and onward is its time, and therefore it is permissible to postpone a circumcision until the ninth day. No answer was found to this question, and the Gemara concludes: Rather, the derivation is clear according to Rabbi Yoḥanan.

It was taught in a baraita in accordance with the opinion of Rabbi Yoḥanan and not in accordance with the opinion of Rav Aḥa bar Ya’akov, as the tanna interprets the phrase: ''On the eighth day he shall be circumcised'' to mean that the circumcision must be performed even on Shabbat. And how do I fulfill the prohibition against performing prohibited labor explicit in the Torah in the verse: ''And you shall guard the Shabbat, for it is holy to you; he who desecrates it shall surely die'' (Exodus 31:14)? That is referring to other prohibited labors besides circumcision. The tanna questions his previous statement: Or perhaps that is not the case, and the prohibition of performing prohibited labor on Shabbat includes even circumcision, and, on the contrary, how do I fulfill the verse: ''On the eighth day he shall be circumcised''? It applies when the eighth day is any day other than Shabbat. The verse states: ''On the day,'' meaning on that very day when he turns eight days old, even on Shabbat. The tanna of this baraita rejects Rav Aḥa bar Ya’akov’s proof and accepts Rabbi Yoḥanan’s assertion that the phrase ''On the day'' conclusively establishes that circumcision is performed even on Shabbat.

With regard to this baraita, Rava said: Initially, what did this tanna find acceptable, and ultimately, what did he find difficult? Initially he suggested that: ''On the eighth day he shall be circumcised'' is a valid source for the fact that circumcision overrides Shabbat, but ultimately, he deemed that difficult and turned to an alternative source, yet provided no reason, neither for his initial statement nor for his second statement.

Rather, we can explain that this is what he is saying: ''On the eighth day he shall be circumcised'' applies even on Shabbat. And how do I fulfill: ''He who desecrates it shall surely die''? That is referring to the other prohibited labors besides circumcision; however, circumcision overrides Shabbat.

What is the reason for this? It is derived by means of an a fortiori inference: Just as leprosy, which overrides the Temple service, as a priest who is a leper may not serve in the Temple and it is prohibited to cut off the symptoms of leprosy,