“And whoever touches one who is slain with a sword in the open field, or one who dies on his own, or a bone of a man, or a grave, shall be unclean seven days” (Numbers 19:16). The Sages derived from the phrase: One who is slain with a sword, that the legal status of a metal sword in terms of its degree of impurity is like that of one who is slain. Any metal vessel that becomes impure through contact with a corpse assumes the impurity status of a corpse, the ultimate primary source of ritual impurity. The same is true with regard to a metal vessel that came into contact with a person or vessel that became impure with impurity imparted by a corpse. In that case the metal vessel assumes the impurity status of that person or vessel, and therefore, this metal lamp is a primary source of impurity. And yet Rabbi Akiva maintains that it is permitted to render this oil, which is impure with third-degree impurity, impure with first-degree impurity through contact with the metal lamp.

The Gemara asks: And what impelled Rav Yehuda to establish the mishna as referring specifically to the case of a metal lamp? Let him establish it as referring specifically to the case of an earthenware lamp.

And if so, what does Rabbi Akiva’s statement add? The Gemara answers: Whereas there, in Rabbi Ḥanina’s testimony, he is referring to a case where one piece of ritually impure meat came into contact with another piece of impure meat, here, in Rabbi Akiva’s testimony, he is referring to a case where oil that is disqualified came into contact with a lamp with first-degree impurity status, rendering the oil impure. Oil with second-degree ritual impurity status disqualifies teruma, as teruma with third-degree ritual impurity status does not transmit ritual impurity to other teruma. In that case, the novelty in Rabbi Akiva’s statement is that a disqualified item is burned together with an impure item even though it is thereby rendered impure.

Rava said: The mishna was difficult for Rav Yehuda: Why did the tanna specifically teach the case of a lamp that became ritually impure with first-degree impurity through contact with one who became ritually impure with impurity imparted by a corpse? Let it teach that the lamp became impure by contact with a creeping animal, which is a much more common primary source of impurity.

Rather, what is the substance with regard to which there is a distinction between its impurity when exposed to impurity imparted by a corpse and its impurity when exposed to impurity imparted by a creeping animal? You must say that the substance is metal. A metal vessel that comes into contact with a creeping animal assumes first-degree ritual impurity status, whereas if it comes into contact with a person or a vessel that came into contact with a corpse, it becomes a primary source of impurity.

Rava said: Learn from this statement that Rabbi Akiva holds: The ritual impurity of liquids with regard to transmitting impurity to other objects is by Torah law, contrary to those tanna’im who hold that liquids transmit impurity only by rabbinic decree. As, if it enters your mind that this type of impurity is by rabbinic law, now, this lamp, what effect does this lamp have on that oil? If it is to disqualify the oil itself, it is already disqualified from the outset. Rather, Rabbi Akiva evidently maintains that through contact with the lamp this oil becomes impure and transmits impurity to food by Torah law.

The Gemara raises a difficulty: From where do you know that this is Rabbi Akiva’s opinion? Perhaps Rabbi Akiva holds that through contact with the lamp, the oil will be able to transmit ritual impurity to other objects by rabbinic law. The Gemara rejects this suggestion: If the oil confers impurity by rabbinic law, why does Rabbi Akiva refer particularly to a case where the oil became impure by contact with a primary source of impurity? If Rabbi Akiva sought to cite an example of rabbinic impurity, he could have cited even a case where the oil came into contact with an object with first-degree impurity status, or an item with second-degree impurity status. By rabbinic law, in those cases too, the oil is impure with first-degree ritual impurity and transmits impurity to food.

The Gemara cites the source for that halakha. As we learned in a mishna: Any item that disqualifies teruma, e.g., anything with second-degree ritual impurity status, transmits impurity to liquids, conferring upon them first-degree ritual impurity status. These liquids assume a higher degree of impurity than the item that rendered them impure. This rabbinic decree applies to anything with second-degree ritual impurity status except for one who was impure and immersed himself during that day and the sun has not yet set. If such a person touches liquids, he does not confer upon them first-degree impurity status. Instead, that case conforms to the standard process of transmission of ritual impurity, and he confers upon them third-degree ritual impurity status and invalidates them.

The Gemara concludes: Rather, learn from the fact that Rabbi Akiva did not cite the example of oil that became impure through contact with an item with first or second-degree ritual impurity that Rabbi Akiva holds that the halakha that liquids transmit impurity to other items is by Torah law.

It was taught in the mishna that Rabbi Meir said: From their statements we learned that one may burn ritually pure teruma with impure teruma when removing leaven on Passover eve. The Gemara asks: From whose statements was this conclusion inferred? If you say that this conclusion is inferred from the statement of Rabbi Ḥanina, the deputy High Priest, is Rabbi Meir’s statement comparable to that case? There, Rabbi Ḥanina said that one may burn one ritually impure item and another ritually impure item together, whereas here, Rabbi Meir is referring to burning pure and impure teruma together.

But rather, Rabbi Meir’s conclusion is inferred from the statement of Rabbi Akiva. Is it comparable to that case? There, Rabbi Akiva said that a disqualified item and an impure item may be burned together, whereas here, Rabbi Meir is referring to burning a pure item and an impure item together.

The Gemara suggests: Let us say that Rabbi Meir maintains that the mishna is referring to an object that is a primary source of impurity by Torah law and an object that is a secondary source of impurity by rabbinic law, which by Torah law is entirely pure. Since the teruma is pure by Torah law, the novelty of Rabbi Meir’s statement is that although by Torah law one of the foods is pure and the other is impure, due to the rabbinic decree of impurity, one may burn the two items together.