Śatapatha Brāhmaṇa ("of a hundred paths") 4.4.3.6

4.4.3.6

athāto gṛhṇātyeva | upayāmagṛhīto 'si harirasi hāriyojano haribhyāṃ tvetyṛkṣāme vai harī ṛkasāmābhyāṃ hyenaṃ gṛhṇāti

He now draws it from that (Âgrayana graha) with (Vâg. S. VIII, it), 'Thou art taken with a support: of bay colour art thou, meet for the team of bay steeds,--thee to the pair of bay steeds!' Now, the two bay horses are the Rik and Sâman: it is for the Rik and Sâman that he draws it.