Śatapatha Brāhmaṇa ("of a hundred paths") 1.9.3.9

1.9.3.9

yadveva viṣṇukramān kramate | yajño vai viṣṇuḥ sa devebhya imāṃ vikrāntiṃ vicakrame yaiṣāmiyaṃ vikrāntiridameva prathamena padena paspārāthedamantarikṣaṃ dvitīyena divamuttamenaitāmvevaiṣa etasmai viṣṇuryajño vikrāntiṃ vikramate tasmādviṣṇukramān kramate tadvā ita eva parācīnam bhūyiṣṭhā iva kramante

And again why he strides the Vishnu-strides, is; Vishnu, truly, is the sacrifice, by striding (vi-kram) he obtained for the gods that all-pervading power (vikrânti) which now belongs to them. By his first step he gained this same (earth), by the second this aërial expanse, and by his last (step) the sky. And this same pervading power Vishnu, as the sacrifice, obtains by his strides for him (the sacrificer): for this reason he strides the Vishnu-strides. Now it is indeed from this (earth) that most (beings) go (upwards).