Śatapatha Brāhmaṇa ("of a hundred paths") 13.8.1.7

13.8.1.7

dakṣiṇāpravaṇe kuryādityāhuḥ dakṣiṇāpravaṇo vai pitṛlokastadenam pitṛloka ābhajatīti na tathā kuryādāmīvaddha nāma tacmaśānakaraṇaṃ kṣipre haiṣāmaparo'nupraiti

'Let him make it on ground inclining towards the south,' they say, 'for the world of the Fathers inclines towards the south: he thus gives him a share in the world of the Fathers.' Let him not do so, however, for, indeed, such a one is an opening tomb, and certainly another of these (members of the dead man's family) quickly follows him in death.