Śatapatha Brāhmaṇa ("of a hundred paths") 1.9.3.21

1.9.3.21

athāhavanīyamupatiṣṭhate | prāṅne yajño 'nusaṃtiṣṭhātā iti tūṣṇīmupatiṣṭhateatha vrataṃ visṛjate | idamahaṃ ya evāsmi so 'smītyamānuṣa iva vā etadbhavati yadvratamupaiti na hi tadavakalpate yadbrūyādidamahaṃ satyādanṛtamupaimīti tadu khalu punarmānuṣo bhavati tasmādidamahaṃ ya evāsmi sā 'smītyevaṃ vrataṃ visṛjeta

Now (in pronouncing the following text) he inserts his son's name: 'May this son (N.N.) carry on this manly deed of mine!' Should he have no son, let him insert his own name.