Shatapatha Brahmana 1.8.3.15

1.8.3.15

sa harati | marutām pṛṣatīrgaceti devalokaṃ gacetyevaitadāha yadāha marutām pṛṣatīrgaceti vaśā pṛśnirbhūtvā divaṃ gaca tato no vṛṣṭimāvahetīyaṃ vai vaśā pṛśniryadidamasyām mūli cāmūlaṃ cānnādyam pratiṣṭhitaṃ teneyaṃ vaśā pṛśniriyam bhūtvā divaṃ gacetyevaitadāha tato no vṛṣṭimāvaheti vṛṣṭādvā ūrgrasaḥ subhūtaṃ jāyate tasmādāha tato no vṛṣṭimāvaheti

He draws it along, with the text (Vâg. S. II, 16 f), 'Go to the spotted (mares) of the Maruts!' He means to say, 'Go to the world of the gods,' when he says, 'Go to the spotted (mares) of the Maruts!'--'Having become a spotted cow, go to the sky and thence bring us rain hither!' The spotted cow, doubtless, is this (earth): whatever rooted and rootless food is here on this (earth), by that this (earth) is a spotted cow. 'Having become this (earth), go thou to the sky!' this is what he thereby says. 'Thence bring us rain hither!' From rain certainly spring vigour, sap, well-being: for this reason he says, 'thence bring us rain hither!