Srimad-Bhagavatam: Canto 5 - Chapter 1 - Verse 9
Sanskrit:
अथ चापूर्यमाणाभिश्च कलाभिरमराणां क्षीयमाणाभिश्च कलाभि: पितृणामहोरात्राणि पूर्वपक्षापरपक्षाभ्यां वितन्वान: सर्वजीवनिवहप्राणो जीवश्चैकमेकं नक्षत्रं त्रिंशता मुहूर्तैर्भुङ्क्ते ॥ ९ ॥
ITRANS:
atha cāpūryamāṇābhiś ca kalābhir amarāṇāṁ kṣīyamāṇābhiś ca kalābhiḥ pitṝṇām aho-rātrāṇi pūrva-pakṣāpara-pakṣābhyāṁ vitanvānaḥ sarva-jīva-nivaha-prāṇo jīvaś caikam ekaṁ nakṣatraṁ triṁśatā muhūrtair bhuṅkte.
Translation:
When the moon is waxing, the illuminating portions of it increase daily, thus creating day for the demigods and night for the pitās. When the moon is waning, however, it causes night for the demigods and day for the pitās. In this way the moon passes through each constellation of stars in thirty muhūrtas [an entire day]. The moon is the source of nectarean coolness that influences the growth of food grains, and therefore the moon-god is considered the life of all living entities. He is consequently called Jīva, the chief living being within the universe.