Taittiriya Upanishad, Shikshavalli, Chapter 3, translated by Sri Aurobindo, concerns itself with “the secret meaning of Sanhita whereof there are five capitals; Concerning the Worlds; Concerning the Shining Fires: Concerning the Knowledge: Concerning Progeny: Concerning Self. These are called the great Sanhitas.”
The Upanishad develops a similar format for explaining each of these, as illustrated: “Now concerning the Worlds. Earth is the first form; the heavens are the second form; ether is the linking; air is the joint of the linking. Thus far concerning the Worlds.”
We see here that earth and heaven are inter-connected and linked. Everywhere we look around us, everything we experience, can be understood through this process of discovering the Oneness and through seeing the symbiotic relationship between all beings. A similar meditation is set forth for the other capitals noted here.
“Fire is the first form; the Sun is the latter form; the waters are the linking; electricity is the joint of the linking.” “The Master is the first form; the disciple is the latter form; Knowledge is the linking; exposition is the joint of the linking.” “The mother is the first form; the father is the latter form; Progeny is the linking; act of procreation is the joint of the linking.” “The upper jaw is the first form; the lower jaw is the latter form; speech is the linking; the tongue is the joint of the linking.”
Gaining a true understanding of the unified field of existence brings with it results and success in the physical, vital and mental worlds: “He who knoweth thus the great Sanhitas as we have expounded them, to him are linked progeny and wealth of cattle and the radiance of holiness and food and all that is of food and the world of his high estate in heaven.”
Sri M. P. Pandit notes: “The mind is to be trained to perceive and conceive newly. Behind the multitudinous variety of forms which people this universe, one must begin to see that there is one underlying Reality which manifests as the many and governs them in an indissoluble unity. Whatever the categories or the terms of the manifestation, they are all interlinked and interdependent. … There is one Principle, one Term of the Sole Being which manifests in several forms — all mutually forming one connected Whole. One must meditate upon this truth in the creation around and let it naturally govern the inlook and outlook.”