This shloka continues the jagat-section that began in 15.12. From 15.7 to 15.11, Bhagavān showed that Brahman alone appears as the jīva in living beings. From 15.12 onward, Bhagavān shows that Brahman alone appears as the inert universe also. In 15.12, Bhagavān pointed to the tejas in the sun, moon, and fire as His own power. Now 15.13 explains more specifically how those natural powers sustain life on earth. Swami’s explanation highlights two major contributions here: sūrya-śakti, solar power, and soma/candra-śakti, lunar nourishing power.

The verse begins: gām āviśya — having entered the earth. Gām means the earth. Āviśya means entering, pervading, or inhering in. Bhagavān is not outside the world like a distant observer. He is present in and through the earth as the sustaining order. The earth is not an independent dead mass accidentally supporting life. The very power by which the earth holds and supports living beings is Bhagavān’s manifestation.

Then Bhagavān says: bhūtāni dhārayāmi aham ojasā — I sustain all living beings with ojas. Here bhūtāni means living beings, not the five elements. Dhārayāmi means I sustain, hold, or support. Ojasā means through energy, vitality, or prāṇa-śakti. Swami connects this especially with the sun’s contribution. The sun sustains the earth and living beings through solar energy. The entire prāṇamaya-kośa is sustained by the sun. Through that prāṇic energy, the annamaya-kośa, physical body, is supported, and even the manomaya-kośa, the mind, is indirectly affected.

This makes the shloka very practical. Sunlight is not merely brightness. It is connected with health, vitality, the body’s rhythm, the functioning of life, and the energy that sustains living beings. Swami mentions daily prayers such as Āditya Hṛdayam and the solar dimension of Sandhyā worship to show that the Vedic tradition did not take the sun casually. It saw solar energy as sacred, life-sustaining, and worthy of reverence.

The second half says: puṣṇāmi ca oṣadhīḥ sarvāḥ — and I nourish all plants. Oṣadhīḥ means plants, herbs, or vegetation. Plants are not nourished by human effort alone. Farmers may prepare soil, sow seeds, and water fields, but the actual life process depends on a vast natural order — earth, sunlight, moonlight, water, nutrients, time, and unseen laws. Bhagavān says: that nourishing power is My manifestation.

Then Bhagavān says: somaḥ bhūtvā rasātmakaḥ — becoming Soma, full of rasa, I nourish all plants. Soma here is connected with the moon, lunar energy. Rasātmakaḥ means of the nature of rasa — sap, juice, nutrient essence, or nourishing power. Swami explains that according to śāstra, moonlight has nutritive power especially for the plant kingdom. The rasa in plants, their sap and nourishing essence, is connected to this lunar energy. Some traditional agricultural practices, such as exposing seeds to moonlight before sowing, reflect this reverential understanding of moon-nourishment.

The deeper point is not to argue that sunlight and moonlight are only religious symbols. The point is to see the sacredness of the natural order. The sun sustains beings through energy and prāṇa. The moon nourishes plants through rasa. Earth holds and supports life. These are not separate from Bhagavān. Bhagavān is not only in a temple, not only in the heart, and not only in a distant heaven. Bhagavān is present as the power by which life is held, nourished, energized, and continued.

This also connects 15.13 back to 15.12. In 15.12, Bhagavān said the light in the sun, moon, and fire is His. In 15.13, He shows the contribution of sun and moon more specifically: solar energy sustains living beings; lunar Soma nourishes plants. The next verse, 15.14, will continue the natural-forces sequence by moving to digestive fire — the power by which food is digested inside the body.

So the teaching movement is: do not look at earth, sun, moon, plants, food, and life as disconnected material things. They are parts of one sacred order. The wise person recognizes Bhagavān as the sustaining power in the earth, the prāṇic power in sunlight, and the nourishing rasa in plants.