Śatapatha Brāhmaṇa ("of a hundred paths") 8.1.3.4

8.1.3.4

tadāhuḥ | yadetattrayaṃ saha kriyate graha stotraṃ śastramathātra grahaṃ caiva stotraṃ copadadhāti kathamasyātrāpi śasramupahitaṃ yadvāva stotraṃ tacastraṃ yāsu hyeva stuvate tā u evānuśaṃsatyevamu hāsyātrāpi śastramupahitam bhavati

As to this they say, 'If these three are done together--the soma-cup, the chant, and the recitation,--and he puts in only the soma-cup and the chant, how comes the recitation also in this case to be put (into the sacrificial work) for him?' But, surely, what the chant is that is the recitation; for on whatsoever (verses) they chant a tune, those same (verses) he (the Hotri) recites thereafter; and in this way, indeed, the Sastra also comes in this case to be put in for him.