Śatapatha Brāhmaṇa ("of a hundred paths") 4.2.5.7

4.2.5.7

atha stotramupākaroti | somaḥ pavata iti sa vai parāgeva stotramupākaroti parāñca stuvate devānvā etāni stotrāṇyabhyupāvṛttāni yatpavamānāḥ parāñco hyetairdevāḥ svargaṃ lokaṃ samāśnuvata tasmātparāgeva stotramupākaroti parāñca stuvate

Then he bespeaks the chant, saying, 'Soma becometh pure!' He bespeaks the chant right off, and they chant right off; for these chants, the Pavamânâh, are directed towards the gods, since the gods thereby attained to the heavenly world right off (straightway): therefore he bespeaks the chant right off, and right off they chant.