Śatapatha Brāhmaṇa ("of a hundred paths") 2.3.4.36

2.3.4.36

yadvā āhavanīyamupatiṣṭhate | divaṃ tadupatiṣṭhate 'tha yadgārhapatyam pṛthivīṃ tadathaitadantarikṣameṣā hi digbṛhaspateretaṃ hyetaddiśamupatiṣṭhate tasmādbārhaspatyaṃ japati

Now when he approaches the Âhavanîya, he approaches the sky; and when (he approaches) the Gârhapatya, (he approaches) the earth. Hereby now (he approaches) the ether, that being Brihaspati's region; and that region he thereby approaches: this is why he mutters the prayer to Brihaspati.