Śatapatha Brāhmaṇa ("of a hundred paths") 1.7.3.12

1.7.3.12

taddhaike | devatām pūrvāṃ kurvantyayāṭkārādagnerayāṭsomasyāyāḍiti tadu tathā na kuryādviloma ha te yajñe kurvanti ye devatām pūrvāṃ kurvantyayāṭkārādidaṃ hi prathamamabhivyāharannayāṭkāramevābhivyāharati tasmādayāṭkārameva pūrvaṃ kuryāt

Here now some make (the name of) the deity precede the 'may he offer (ayât)!' thus--'Of Agni may he offer (the favourite dainties)!' 'Of Soma may he offer!' But let him not do this; for those who make the deity precede the 'may he offer!' violate the proper order at the sacrifice, since it is by pronouncing the 'may he offer,' that he pronounces what comes first here: let him therefore place the 'may he offer' first.