Śatapatha Brāhmaṇa ("of a hundred paths") 1.6.4.10

1.6.4.10

tadāhuḥ | nāsomayājī saṃnayetsomāhutirvā eṣā sānavaruddhāsomayājinastasmānnāsomayājī sanayediti

In reference to this point they say, 'One who has not performed the Soma-sacrifice, must not offer the Sânnâyya; for, indeed, the Sânnâyya is (of the same significance as) a Soma libation, and the latter is not permitted to one who is not a Soma-sacrificer: hence he who has not performed the Soma-sacrifice, must not offer the Sânnâyya.'