Sri Aurobindo translates Chapter 2, Section 1, Verses 9 and 10 as follows: “From Him are the oceans and all these mountains and from Him flow rivers of all forms, and from Him are all plants, and sensible delight which makes the soul to abide with the material elements. The Spirit is all this universe; He is works and askesis and the Brahman, supreme and immortal. O fair son, he who knows this hidden in the secret heart, scatters even here in this world the knot of the Ignorance.”
When we experience the beauty and wonder of the world, as we open ourselves up to Nature, we can recognise that the Divine is the Source of all this. We experience a delight of existence which causes us to wish to live and continue to experience the world. The Taittiriya Upanishad makes this point in a very direct manner: “Lo, this that is well and beautifully made, verily it is no other than the delight behind existence. When he hath gotten him this delight, then it is that this creature becometh a thing of bliss; for who could labour to draw in the breath or who could have strength to breathe it out, if there were not that Bliss in the heaven of his heart, in the ether within his being? (Sri Aurobindo, The Upanishads, pg. 271) Almost all people experiencing numerous hardships in life have the desire to live and extend their lives, despite promises of heavens beyond. The aspiration for life comes from the delight of existence hidden in the “secret heart”.
Brahman is all that we see, all that we experience, all that exists–there is no other. The Brahman is also all our actions, works, and concentration of conscious force, tapas, often translated as “askesis”. He who recognizes this knowledge in the secret heart of his being has gained the higher knowledge and is no longer misled by the multiplicity of outer forms, forces and actions that otherwise distract us and make us believe that existence consists of a number of separate, fragmented beings. The appearances of separation, and the ability to act in response to these appearances, remains the province of the lower knowledge; the understanding of the unity of all these apparently separate things is the higher knowledge. Brahman cannot be known through mental formulation — the sage experiences Brahman through a knowledge by identity which arises in the “secret heart”. This is the Knowledge of unity which overcomes the Ignorance of separate existence.
Sri Aurobindo, The Upanishads, Mundaka Upanishad, pp. 193-210