Bṛhadāraṇyaka Upaniṣad ("Great Forest Teaching") 3.8.9

3.8.9

etasya vā akṣarasya praśāsane gārgi sūryācandramasau vidhṛtau tiṣṭhata etasya vā akṣarasya praśāsane gārgi dyāvāpṛthivyau vidhṛte tiṣṭhata etasya vā akṣarasya praśāsane gārgi nimeṣā muhūrtāahorātrāṇyardhamāsā māsā tavaḥ saṃvatsarā iti vidhṛtāstiṣṭhantyetasya vā akṣarasya praśāsane gārgi prācyo'nyā nadyaḥ syandante śvetebhyaḥ parvatebhyaḥ pratīcyo'nyā yāṃ yāṃ ca diśamanvetasya vā akṣarasya praśāsane gārgi dadato manuṣyāḥ praśam̐santi yajamānaṃ devā davim̐ pitaro'nvāyattāḥ

'By the command of that Akshara (the imperishable), O Gârgî, sun and moon stand apart. By the command of that Akshara, O Gârgî, heaven and earth stand apart. By the command of that Akshara, O Gârgî, what are called moments (nimesha), hours (muhûrta), days and nights, half-months, months, seasons, years, all stand apart. By the command of that Akshara, O Gârgî, some rivers flow to the East from the white mountains, others to the West, or to any other quarter. By the command of that Akshara, O Gârgî, men praise those who give, the gods follow the sacrificer, the fathers the Darvî-offering.'