Shatapatha Brahmana 10.4.1.13

10.4.1.13

tamadhvaryurgraheṇa gṛhṇāti yadgṛhṇāti tasmādgrahastasminnudgātā mahāvratena rasaṃ dadhāti sarvāṇi haitāni sāmāni yanmahāvrataṃ tadasmintsarvaiḥ sāmabhī rasaṃ dadhāti tasminhotā mahatokthena rasaṃ dadhāti sarvā haitā ṛco yanmahadukthaṃ tadasmintsarvābhirṛgbhī rasaṃ dadhāti

The Adhvaryu draws it by means of a cup, and inasmuch as he draws (grah) it, it is (called) a draught (graha, cup of Soma). The Udgâtri (chanter), by the Mahâvrata (sâman), puts flavour (vital sap) into it; and the Mahâvrata (sâman) being (composed of) all those (five) sâmans, he thus puts flavour into it by means of all sâmans (hymn-tunes). The Hotri puts flavour into it by means of the Great Recitation; and the Great Recitation being (composed of) all those Rik-verses: he thus puts flavour into it by all the Rik-verses.