Śatapatha Brāhmaṇa ("of a hundred paths") 6.1.2.1

6.1.2.1

so 'kāmayata prajāpatiḥ | bhūya eva syātprajāyeteti so 'gninā pṛthivīm mithunaṃ samabhavattata āṇḍaṃ samavartata tadabhyamṛśatpuṣyatviti puṣyatu bhūyo 'stvityeva tadabravīt

That Pragâpati desired, 'May it multiply, may it be reproduced!' By means (or, in the form) of Agni he entered into union with the Earth: thence an egg arose. He touched it: 'May it grow! May it grow and multiply!' he said.