Rabbi Akiva’s testimony is not needed to teach the basic halakha that a vessel combines its ingredients, which is Torah law; it is necessary only for the remainders of the meal-offering, the part of a meal-offering left over after a fistful of it and its frankincense have been sacrificed on the altar, which is eaten by a priest. In such a case the halakha of combining applies only by rabbinic law, for by Torah law only when an item requires a vessel in order for it to be sanctified does the vessel combine it with regard to impurity, even if its parts are not touching each other. But in the case of something that does not require a vessel, the vessel does not combine it. The remainder of a meal-offering no longer requires a vessel, since it is given to a priest after the fistful is sacrificed, so the flour in a vessel would not be considered combined according to Torah law.

And the Sages came and decreed that even if something does not require a vessel, such as the leftover flour of the meal-offering, the vessel nevertheless combines it.

The Gemara raises a difficulty: It works out well in the case of flour, which can be said to refer to the flour left over from meal-offerings, but with regard to incense and frankincense, what is there to say? In these cases a vessel is certainly required, but if the halakha of combining applies to them from the Torah, why did Rabbi Akiva include them in his list? Rav Naḥman said that Rabba bar Avuh said: For example, if he piled them up on a leather board [kartavla], rather than in a containing vessel. By Torah law a vessel that has an inside combines its ingredients, but one that is flat and does not have an inside does not combine. And the Sages came and decreed that even if it does not have an inside it nevertheless combines what is placed on it.

The Gemara comments: And this opinion of Rabbi Ḥanin’s, that impurity by combining is derived from the Torah, disagrees with the opinion of Rabbi Ḥiyya bar Abba. For Rabbi Ḥiyya bar Abba said that Rabbi Yoḥanan said in reference to our mishna: This mishna was taught based on Rabbi Akiva’s testimony. In other words, the mishna’s teaching that a vessel combines its contents follows the statement of Rabbi Akiva, indicating that it is by rabbinic law, unlike Rabbi Ḥanin, who said that it is based on a source from the Torah.

§ It was taught in the mishna: The fourth degree of impurity, with regard to sacrificial food, is disqualified. It is taught in a baraita: Rabbi Yosei said: From where is it derived with regard to the fourth degree of ritual impurity, that with regard to sacrificial food it is disqualified? It is a logical derivation, by a fortiori: If one who is lacking atonement, an impure person who is obligated to bring an offering to complete his purification process, who is permitted to eat teruma, is nevertheless disqualified with regard to the consumption of sacrificial food, as specified in the Torah, then concerning something that is impure to the third degree of ritual impurity, which is disqualified if it is teruma, is it not right that it should engender a fourth degree of ritual impurity when it touches sacrificial food? Therefore, we have learned that there is a third degree of impurity with regard to sacrificial food from the Torah, and that there is a fourth degree of impurity from a fortiori reasoning.

The above baraita taught that there is a third degree of impurity for sacrificial food from the Torah. The Gemara asks: From where is this derived? As it is written: “And the meat that touches any impure thing shall not be eaten” (Leviticus 7:19). Is it not so that we are not dealing in that verse with meat that touches any “impure thing” at all, even if it touched something that is of the second degree of ritual impurity, which is also called an “impure thing”? And yet the Merciful One states with regard to that meat, which having touched a second-degree impurity is now impure to the third degree: “It shall not be eaten,” meaning that it has been rendered unfit due to impurity. And as for the baraita’s statement that the fourth level of impurity is derived by an a fortiori inference – it is as we said just above, the a fortiori inference put forth by Rabbi Yosei.

§ It was taught in the mishna: And with regard to teruma, if one of one’s hands became impure with impurity by rabbinic law that renders only the hands impure, its counterpart, the other hand, remains pure. But with regard to sacrificial food, if one hand becomes impure he must immerse them both. Rav Sheizevi said: When they said that with regard to sacrificial food a hand that is rendered impure renders the other hand impure as well, they taught this only for a situation when the pure hand is in contact with the sacrificial food when the impure hand touches it. But if the pure hand is not in contact with the sacrificial food, no, the pure hand is not rendered impure by touching the impure hand. According to Rav Sheizevi, the Sages enacted the decree that one hand renders the other impure because they were concerned that the impure hand may have touched the sacrificial food directly without being noticed. Therefore, the decree applies only when the pure hand is touching the sacrificial food.

Abaye raised an objection to Rav Sheizevi from the following teaching: Even a dry hand that is impure renders its counterpart, i.e., the other hand, impure, to the extent that the second hand will now render impure any food that it touches. This is true with regard to sacrificial food but not with regard to teruma. This is the statement of Rabbi Yehuda HaNasi. Rabbi Yosei, son of Rabbi Yehuda, says: The second hand is not rendered impure to such a severe extent. It can merely disqualify sacrificial food that it touches, by rendering it impure to the fourth degree, but not render it impure with third-degree impurity.

Granted, if you say that the second hand becomes impure even when it is not in contact with the sacrificial food, this would explain the noteworthiness of a dry hand rendering its counterpart impure. It teaches that even though normally a dry hand would not render another hand impure, the Sages nevertheless declared it impure with regard to sacrificial food. But if you say that when the second hand is in contact with sacrificial food, yes, the decree that the second hand becomes impure applies, lest the impure hand touch the sacrificial food directly, but when it is not in contact, no, the decree does not apply, then what is the noteworthiness of stating that it applies in the case of a dry hand?

It was also stated that amora’im disputed a similar issue: Reish Lakish said: They taught that one hand renders the other impure only if the second hand is his own hand,