Śatapatha Brāhmaṇa ("of a hundred paths") 1.4.1.22

1.4.1.22

agna āyāhi vītaya iti | tadveti bhavati vītaya iti samantikamiva havā ime 'gre lokā āsurityunmṛśyā haiva dyaurāsa

[He recites the second sâmidhenî]: 'Come hither, Agni, to expand!'--'To expand' he says, because at the beginning these worlds were well-nigh contiguous to one another: at that time one could touch the sky thus.