Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.2.8

4.1.2.8

tadyadupayāmena grahā gṛhyante | iyaṃ vā upayāma iyaṃ vā idamannādyamupayacati paśubhyo manuṣyebhyo vanaspatibhya ito vā ūrdhvā devā divi hi devāḥ

And, again, why the grahas are drawn with the Upayâma. The Upayâma indeed is this (earth), since it is this (earth) that bears (upa-yam) food here for cattle and men and trees; and the gods are above this, for the gods are in heaven.