Śatapatha Brāhmaṇa ("of a hundred paths") 1.7.4.4

1.7.4.4

te ha devā ūcuḥ | yo 'yaṃ devaḥ paśūnāmīṣṭe 'tisaṃdhaṃ vā ayaṃ carati ya itthaṃ svāṃ duhitaramasmākaṃ svasāraṃ karoti vidhyemamiti taṃ rudro 'bhyāyatya vivyādha tasya sāmi retaḥ pracaskanda tathennūnaṃ tadāsa

Accordingly it has been said by the Rishi with reference to that (incident), 'When the father embraced his daughter, uniting with her, he dropped his seed on the earth.' This (became) the chant (uktha) called âgnimâruta; in (connection with) this it is set forth how the gods caused that seed to spring. When the anger of the gods subsided, they cured Pragâpati and cut out that dart of this. (Rudra); for Pragâpati, doubtless, is this sacrifice.