Shatapatha Brahmana 1.9.1.1

1.9.1.1

sa yatrāha | iṣitā daivyā hotāro bhadravācyāya preṣito mānuṣaḥ sūktavākāyeti yadato hotānvāha sūkta iva tadāha yajamānāyaivaitadāśiṣamāśāste tadvā etadupariṣṭādyajñasyāśiṣamāśāste dvayaṃ tadyasmādupariṣṭādyajñasyāśiṣamāśāste

Now when (the Adhvaryu) says, 'The divine Hotris are summoned for the proclamation of success, the human one is called upon for the song of praise (sûkta-vâka);' and when the Hotri thereupon recites, he recites good words only: he thereby invokes a blessing on the sacrificer. It is indeed after the sacrifice that he thus invokes a blessing. A twofold reason there is for his invoking the blessing after the sacrifice.