Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.1.1

3.1.1.1

devayajanaṃ joṣayante | sa yadeva varṣiṣṭhaṃ syāttajjoṣayeranyadanyadbhūmerābhiśayītāto vai devā divamupodakrāmandevānvā eṣa upotkrāmati yo dīkṣate sa sadeve devayajane yajate sa yaddhānyadbhūmerabhiśayītāvaratara iva heṣṭhvā syāttasmādyadeva varṣiṣṭhaṃ syāttajjoṣayeran

They choose a place of worship. Let them choose (the place) which lies highest, and above which no other part of the ground rises; for it was from thence that the gods ascended to heaven, and he who is consecrated indeed ascends to the gods. He thus sacrifices on a place of worship frequented by the gods; but were any other part of the ground to rise above it, he would indeed be lowered while sacrificing: let them therefore choose (the place) which lies highest.