Śatapatha Brāhmaṇa ("of a hundred paths") 1.4.1.23

1.4.1.23

te devā akāmayanta | kathaṃ nu na ime lokā vitarāṃ syuḥ kathaṃ na idaṃ varīya iva syāditi tānetaireva tribhirakṣarairvyanayanvītaya iti ta ime viṭūraṃ lokāstato devebhyo varīyo 'bhavadvarīyo ha vā asya bhavati yasyaivaṃ viduṣa etāmanvāhurvītaya iti

The gods desired, 'How could these worlds of ours become farther apart from one another? How could there be more space for us?' They breathed through them (the worlds) with these three syllables (forming the word) 'vîtaye,' and these worlds became far apart from one another; and there was then ampler space for the gods: ample space, therefore, he will have for whom, knowing this, they recite this (verse) containing (the word) 'vîtaye.'