Pesachim 15A

ומאי ״מדבריהם״⁠ — מדברי רבי חנינא סגן הכהנים.

And what did R' Meir mean when he said: From their statements? He meant: From the statement of R' Ḥanina the deputy High Priest.

אמר ריש לקיש משום בר קפרא: מתניתין באב הטומאה דאורייתא וולד הטומאה דאורייתא, ומאי ״מדבריהם״, מדברי רבי אליעזר ורבי יהושע.

Reish Lakish said another explanation of the Mishnah in the name of bar Kappara: The case in the Mishnah is one involving a primary source of ritual impurity by Torah law and a secondary source of impurity by Torah law. And what did R' Meir mean by the phrase: From their statements? He was not referring to the tanna’im in this Mishnah, but rather: From the statements of R' Eliezer and R' Yehoshua cited elsewhere.

הי רבי יהושע? אילימא הא רבי יהושע דתנן: חבית של תרומה שנולד לה ספק טומאה, רבי אליעזר אומר: אם היתה מונחת במקום התורפה, יניחנה במקום המוצנע, ואם היתה מגולה ⁠— יכסנה.

The Talmud asks: To which statement of R' Yehoshua is R' Meir referring? If you say he is referring to this statement of R' Yehoshua, as we learned in a Mishnah: In the case of a jug of teruma produce with regard to which uncertainty developed with regard to its impurity, and which therefore may not be eaten, R' Eliezer says that one must nevertheless safeguard the teruma from ritual impurity. Therefore, he maintains: If the jug was resting in a vulnerable place, where it may come into contact with impurity, one should place it in a concealed place, and if it was exposed, he should cover it.

רבי יהושע אומר: אם היתה מונחת במקום המוצנע ⁠— יניחנה במקום התורפה, ואם היתה מכוסה ⁠— יגלנה.

R' Yehoshua says: That is not necessary. Rather, even if it was placed in a concealed place, he may place it in a vulnerable place if he chooses. And if it was covered, he may expose it, as he need no longer safeguard this teruma from impurity. According to R' Yehoshua, as teruma whose impurity status is uncertain, may be used only for lighting a fire, there is no requirement to prevent it from contact with ritual impurity. The same reasoning applies to pure leaven: One is not required to safeguard it from impurity in the process of its removal.