Mimamsasutra 3.2.25

3.2.25

atraiva gurumatamāha -
kalpe sarvatithau darśakāryatokteḥ śrutirna mā |
na kalpe sādhyavedatvaprahāṇāddurbalatvataḥ ||

On this very point, he states the Guru's [Prabhākara's] view:
Because the performance of the new-moon sacrifice on all lunar days is stated in the Kalpa, direct Vedic statement is not a means of valid cognition.
Not so; because its status as Veda in the Kalpa has been abandoned, as it is to be established, and because it is weaker.