Aitareyabrahmana 3.3.p14

3.3.p14

the offering verse for (the pap for) Soma is addressed to Soma, the offering verse for the ghee is addressed to Viṣṇu. For (the pap for) Soma he uses as offering verse ‘Thou, O Soma, in unison with the fathers,’ which contains (the word) ‘fathers’. They slay the Soma in that they press it; for it they perform (the offering of) a barren cow in the form of (the pap) for Soma; the barren cow is for the fathers; therefore (a verse) containing (the word) ‘fathers’ he uses as offering verse for (the pap for) Soma. They have killed Soma in that they pressed it; thus do they again bring it into being; they swell it up again with the symbol of the Upasads, these deities, Agni, Soma, and Viṣṇu are the symbol of the Upasads. Having taken (the pap) for Soma before the Sāman singers the Hotṛ should look into it; some indeed give it first to the Sāman singers, but that he should not do. ‘The sayer of vaṣaṭ eats first all foods’, he used to say; in this way therefore the sayer of vaṣaṭ should first look into it, then they give it to the Sāman singers.