तेजोऽशितं त्रेधा विधीयते तस्य यः स्थविष्ठो धातुस्तदस्थि भवति यो मध्यमः स मज्जा योऽणिष्ठः सा वाक् ॥ ६.५.३ ॥
tejo’śitaṃ tredhā vidhīyate tasya yaḥ sthaviṣṭho dhātustadasthi bhavati yo madhyamaḥ sa majjā yo’ṇiṣṭhaḥ sā vāk || 6.5.3 ||
3. When we eat fire [i.e., butter, oil, etc.], it divides itself into three parts. The grossest part of it becomes bone; that which is less gross becomes marrow; and the subtlest part becomes speech.
Tejaḥ aśitam, when fire [i.e., oil, butter, etc., which produce energy] is eaten; tredhā, in three ways; vidhīyāte, is divided; tasya, of it; yaḥ sthaviṣṭhaḥ, that which is the grossest; dhātuḥ, part; tat asthi bhavati, that becomes bone; yaḥ madhyamaḥ, that which is midway; saḥ majjā, that [becomes] marrow; yaḥ aṇiṣṭhaḥ, that which is the subtlest; sā vāk, that is speech.
Tejas literally means ‘fire.’ The idea here is that if you eat butter or fatty substances such as oil, it is like eating fire. Why? Because butter and oil are sources of tejas—that is, they provide us energy and vitality. These substances, when eaten, also become transformed into three different things. That which is gross becomes our bones; that which is between the gross and the subtle becomes our marrow; and that which is subtle becomes our speech. If our organ of speech is supported by the right kind of food, we are able to speak logically and articulately.
The Upaniṣad is showing us here how we depend on these elements—earth, water, and fire. We. are able to think, speak, and move about all because of the support we get from them. But all these things depend on Brahman, pure Spirit. If you think of the way nature functions, and how the planets rotate in their orbits, and so forth, you are extremely impressed. Everything is so well organized. But we must remember, it is Brahman that is manifesting as nature, as the planets, as you and me and each individual—as even the tiny insects. The idea is that the One has become the many. Let us not be deluded by seeing the many.