Zevachim 99B

ומגריפה בתוכו, ואמר: ״לבי על הסל ואין לבי על המגריפה״⁠ – הסל טהור והמגריפה טמאה.

and a shovel was in the basket, and he said: I am minding the basket, that it not become impure, but I am not minding the shovel, then the basket is pure, and the shovel is impure.

ותטמא מגריפה לסל! אין כלי מטמא כלי. ותטמא מה שבתוכו! אמר רבא: באומר שמרתיה מדבר המטמאה, ולא שמרתיה מדבר הפוסלה.

The Talmud challenges the ruling of the baraita: But wouldn’t the shovel render the basket impure? The Talmud answers: There is a principle that a vessel does not render another vessel ritually impure. The Talmud challenges: But wouldn’t the shovel render that which is in the basket, e.g., figs, impure? Rava said: The case is where he says: I safeguarded it, the shovel, from anything that would allow it to render another item impure, but I did not safeguard it from anything that would render it itself unfit, i.e., impure.

איגלגל מילתא, ומטאי לקמיה דרבי אבא בר ממל. אמר להו, לא שמיע להו הא דאמר רבי יוחנן אמר רבי: האוכל שלישי של תרומה ⁠– אסור לאכול ומותר ליגע?

The Talmud returns to discuss the contradiction between the Mishnah, which permits an acute mourner to touch sacrificial meat, and the Mishnah in tractate Ḥagiga, which requires him to immerse. The Talmud relates: The matter circulated and came before R' Abba bar Memel. He said to the rabbis before him: Have they not heard that which R' Yoḥanan says that R' Yehuda HaNasi says: One who partakes of teruma that has 3rd-degree impurity, i.e., teruma disqualified through contact with an item with 2nd-degree impurity, is prohibited from partaking of teruma, but permitted to touch teruma.

אלמא באכילה עבוד רבנן מעלה, בנגיעה לא עבוד רבנן מעלה!

R' Abba bar Memel continued: Apparently, in a case of partaking, the rabbis imposed a higher standard, whereas in a case of touching, the rabbis did not impose a higher standard. Similarly, in a case of an acute mourner, the rabbis require him to immerse before he may partake of sacrificial meat, as taught in tractate Ḥagiga, but they do not impose this standard for touching the meat, as taught in the Mishnah here.