There is a proverb that day for most people is night for the seer; and that night for most people is day for the seer. If we reflect, for a moment, on the characteristics of day and night, we can appreciate the sense of this proverb. During the day our attention is focused on the world around us and our life on this globe. During the night, we become aware of infinite space and myriads of stars that exist outside the small confines of our world. Our perspective widens and we experience a sense of eternity.
The Upanishads speak of the Eternal. They move us away from the focus solely on the ego-personality and the outer world to reconnect us with the Eternal and make the Eternal the basis for how we think, live and act.
4th part, Verse 7: “Thou has said, ‘Speak to me Upanishad’; spoken to thee is Upanishad. Of the Eternal verily is the Upanishad that we have spoken.”
Sri Aurobindo notes: “This is the culmination of the teaching of the Upanishad; there was a demand for the secret teaching that enters into the ultimate truth, for the ‘Upanishad’, (Upanishad means inner knowledge, that which enters into the final Truth and settles in it.) and in response this doctrine has been given. It has been uttered, the Upanishad of the Brahman, the hidden ultimate truth of the supreme Existence; its beginning was the search for the Lord, Master of mind, life, speech and senses in whom is the absolute of mind, the absolute of life, the absolute of speech and senses and its close is the finding of Him as the transcendent Beatitude and the elevation of the soul that finds and possesses it into a living centre of that Delight towards which all creatures in the universe shall turn as to a fountain of its ecstasies.”
Sri Aurobindo, The Upanishads, Kena Upanishad and analysis, pg. 107, 177-183