Śatapatha Brāhmaṇa ("of a hundred paths") 6.1.2.34

6.1.2.34

atho dvāviti brūyāt | avī itīyaṃ cāsau ceme hīmāḥ sarvāḥ prajā avato yanmṛdiyaṃ tadyadāpo 'sau tanmṛccāpaśceṣṭakā bhavanti tasmāddāviti brūyāt

Or, 'Two,' he may say, 'two sheep;' for sheep, indeed, are both this (earth) and that (sky), since these two favour all these creatures;--what clay (there is in the brick) that is this earth; and what water there is that is that sky; and the bricks consist of clay and water: therefore he may say, 'Two.'