Pesachim 81B

אינו דין שהותרה לו טומאת התהום!

is it not right that impurity of the deep is permitted for him completely, even if there are other priests who are ritually pure?

אמרי: ומי דיינינן קל וחומר מהלכה? והתניא, אמר לו רבי אליעזר: עקיבא, עצם כשעורה הלכה, רביעית דם קל וחומר, ואין דנין קל וחומר מהלכה!

Say in refutation of this proof: And do we derive an a fortiori inference from a halakha transmitted to Moses from Sinai, such as the halakha of ritual impurity of the deep? Wasn’t the following taught in a baraita? R' Akiva employed an a fortiori inference to derive that a nazirite must shave if he touches or carries blood, just as he must shave if he touches or carries a bone from a corpse, and R' Eliezer said to him: Akiva, a bone the size of a grain of barley is able to transmit ritual impurity due to a halakha transmitted to Moses from Sinai, and you want to derive that the same is true of 1/4th-log of blood on the basis of an a fortiori inference, and one may not derive an a fortiori inference from a halakha transmitted to Moses from Sinai.

אלא אמר רבא: יליף ״מועדו״ ״מועדו״ מפסח.

Rather, Rava said: It is derived on the basis of a verbal analogy of the expressions “its appointed time” (Numbers 9:13) stated with regard to the Paschal lamb, and “its appointed time” (Numbers 28:2) stated with regard to the daily offering. Since the Torah uses this expression in both cases, the halakha with regard to the daily offering can be derived from the halakha in the case of the Paschal lamb: Just as impurity of the deep is permitted with regard to the Paschal lamb, it is permitted with regard to the daily offering.