Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.3.19

4.3.3.19

athopākṛtyaitāṃ vācaṃ vadati | abhiṣotāro 'bhiṣuṇutaulūkhalānudvādayatāgnīdāśiraṃ vinaya saumyasya vittāditi te vai tṛtīyasavanāyaivābhiṣotāro 'bhiṣuṇvanti tṛtīyasavanāyaulūkhalānudvādayanti tṛtīyasavanāyāgnīdāśiraṃ vinayati tṛtīyasavanāya saumyaṃ caruṃ śrapayatyete vai śukravatī rasavatī savane yatprātaḥsavanaṃ ca mādhyandinaṃ ca savanamathaitannirdhītaśukraṃ yattṛtīyasavanaṃ tadevaitasmānmādhyandinātsavanānnirmimīte tatho hāsyaitacukravadrasavattṛtīyasavanam bhavati tasmādetāmatra vācaṃ vadati

And having bespoken (the chant), he says this speech,--'Pressers, press ye! make the mortars resound! Agnîdh, stir the sour milk! be thou mindful of Soma's (pap)!' It is for the evening's press-feast that those pressers press out (the Soma juice), for the evening feast they make the mortars resound, for the evening feast the Agnîdh stirs the sour milk, for the evening feast he boils the pap for Soma. For these two press-feasts, the morning feast and the midday feast, are indeed rich in pure Soma, are rich in juice; but that third press-feast is emptied of the pure Soma. Hence he forms it from out of this midday feast; and thus that third press-feast becomes for him rich in pure Soma, rich in juice: this is why he now speaks that speech.