Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.1.2

3.1.1.2

tadvarṣma satsamaṃ syāt | samaṃ sadavibhraṃśi syādavibhraṃśi satprākpravaṇaṃ syātprācī hi devānāṃ digatho udakpravaṇamudīcī hi manuṣyāṇāṃ digdakṣiṇataḥ pratyucritamiva syādeṣā vai dik pitṝṇāṃ sa yaddakṣiṇāpravaṇaṃ syātkṣipre ha yajamāno 'muṃ lokamiyāttatho ha yajamāno jyogjīvati tasmāddakṣiṇataḥ pratyucritamiva syāt

While being high, that place should be even; and being even, it should be firm; and being firm, it should incline towards the east, since the east is the quarter of the gods; or else it should incline towards the north, since the north is the quarter of men. It should rise somewhat towards the south, that being the quarter of the Fathers. Were it to incline towards the south, the sacrifice would quickly go to yonder world; but in this way the sacrificer lives long: let it therefore rise somewhat towards the south.