Śatapatha Brāhmaṇa ("of a hundred paths") 3.4.3.12

3.4.3.12

tadāhuḥ | yasmā etadāpyāyanaṃ kriyata ātithyaṃ somāya tamevāgra āpyāyayeyurathāvāntaradīkṣāmatha tānūnaptrāṇīti tadu tathā na kuryādyajñasya vā evaṃ karmātra vā enāntsamadavindatte saṃśamameva pūrvamupāyannathāvāntaradīkṣāmathāpyāyanam

Here now they say, 'Him, Soma, for whom that strengthening (meal), the guest-offering, is prepared, they ought first to strengthen, and then (ought to be performed) the Avântaradîkshâ, and thereupon the Tânûnaptra.' But let him not do this. For such indeed was the course of the sacrificial performance: discord arose between them (the gods) thereat; they attained to their former tranquillity; then the Avântaradîkshâ and finally the strengthening.