The Prashna Upanishad with Shankara’s Commentary
आदित्यो ह वै प्राणो रयिरेव चन्द्रमा रयिर्वा एतत्सर्वं यन्मूर्तं चामूर्तं च तस्मान्मूर्तिरेव रयिः ॥ ५ ॥
ādityo ha vai prāṇo rayireva candramā rayirvā etatsarvaṃ yanmūrtaṃ cāmūrtaṃ ca tasmānmūrtireva rayiḥ || 5 ||
5. The sun is life, indeed, and the moon, the food; all this having form and formless is food; so form is certainly food.
Com.—Here the sun is prâna, the eater, the fire the moon is the food, the moon is, indeed, food. This pair, the eater and the food really one, different aspects of the lord of creatures. The distinction is really one of secondary and primary. How? all this gross and subtle, is, indeed, in one aspect food, both having form and formless, the eater and the food. Therefore, when a dinner is made, i.e., what has form and what has not; (the former) is food being eaten by what is formless.