Śatapatha Brāhmaṇa ("of a hundred paths") 2.3.3.12

2.3.3.12

sa yathā rathopasthe tiṣṭhan | upariṣṭādrathacakre palyaṅyamāne upāvekṣetaivam parastādarvācīno 'horātre upāvekṣate naha vā asyāhorātre sukṛtaṃ kṣiṇuto ya evametāmahorātrayoratimuktiṃ veda

And as, while standing inside a chariot, one would look down from above on the revolving chariot-wheels, even so does he look down from on high upon day and night: and, verily, day and night destroy not the reward of him who thus knows that release from day and night.