Śatapatha Brāhmaṇa ("of a hundred paths") 2.2.4.12

2.2.4.12

te stutvā prāñca uccakramuḥ | punarema iti devā edgāṃ sambhūtāṃ sā hainānudīkṣya hiṃcakāra te devā vidāṃ cakrureṣa sāmno hiṃkāra ityapahiṃkāraṃ haiva purā tataḥ sāmāsa sa eṣa gavi sāmno hiṃkārastasmādeṣopajīvanīyopajīvanīyo ha vai bhavati ya evametaṃ gavi sāmno hiṃkāraṃ veda

When they had sung praises, they went out towards the east, saying, 'We (will) go back thither!' The gods came upon a cow which had sprung into existence. Looking up at them, she uttered the sound 'hiṅ.' The gods perceived that this was the 'Hiṅ' of the Sâman (melodious sacrificial chant); for heretofore (their song was) without the but after that it was the (real) Sâman. And as this same sound 'Hiṅ' of the Sâman was in the cow, therefore the latter affords the means of subsistence; and so does he afford the means of subsistence whosoever thus knows that 'Hiṅ' of the Sâman in the cow.