Shatapatha Brahmana 5.1.3.14

5.1.3.14

tadu tathā na kuryāt | hvalati vā eṣa yo yajñapathādetyeti vā eṣa yajñapathādya evaṃ karoti tasmādyatraivetareṣām paśūnāṃ vapābhiḥ pracaranti tadevaiteṣāṃ vapābhiḥ pracareyuryavetareṣām paśūnāṃ havirbhiḥ pracaranti tadevaiteṣāṃ haviṣā pracareyurekānuvākyā ekā yājyaikadevatyā hi prajāpataya ityupāṃśūktvā cāgānāṃ haviṣo 'nubrūhīti prajāpataya ityupāṃśūktvā cāgānāṃ haviḥ prasthitam preṣyeti vaṣaṭkṛte juhoti

But let him not do it in this wise for he who departs from the path of the sacrifice stumbles; and he who does it in this wise certainly departs from the path of the sacrifice. Hence whenever they proceed with the omenta of the other victims, let them at the same time proceed with the omenta of these; and whenever they proceed with the (chief) oblations of the other victims, let them at the same time proceed with the oblations of these. There is but one invitatory prayer, and one offering prayer; for (these offerings) belong to one deity. He says (to the Maitrâvaruna), 'To Pragâpati'--saying this (name) in a low voice--'recite the invitatory prayer for the offering of the bucks!'--'To Pragâpati' saying this in a low voice--'urge the ready-standing offering of the bucks!' and as the Vashat is uttered, he makes the offering.