Shatapatha Brahmana 2.2.4.11

2.2.4.11

ta u haita ūcuḥ | vayaṃ vai prajāpatim pitaramanu smo hanta vayaṃ tatsṛjāmahai yadasmānanvasaditi te pariśritya gāyatreṇāpahiṃkāreṇa tuṣṭuvire tadyatparyaśrayantsa samudro 'theyameva pṛthivyāstāvaḥ

They then said, 'We come after our father Pragâpati: let us then create what shall come after us!' Having enclosed (a piece of ground), they sang praises with the gâyatrî stanza without the 'Hiṅ:' and that (with) which they enclosed was the ocean; and this earth was the praising-ground (âstâva).