In the Isha Upanishad (perhaps meaning hidden or enveloped in the lord or ruler), there is an acknowledgement of the distinction between the ‘transient’ and the ‘eternal.’ In the opening line, the eternal is identified as superior to the transient. One who dwells exceedingly on the latter will descend into darkness, but one who acts according to the former, and sees himself in light of all things in the cosmos, loses fear. Christianity embraces a like-minded dualism, though the self is not annihilated or subjugated to the greater universe.
Similar to the project embarked upon by Lucretius in his later Epicurean work entitled De Rerum Natura, the Isha Upanishad attempts to address man’s primal fear. This fear is best described as the terror of death in light of eternity, or the gripping fear that comes from an awareness of the cold, purposeless, and chaotic cosmos. The author advises us to see ourselves in everything, and thus to lose fear. Death is not unique, as it would be infinitely to the solipsist, but rather a part of the greater unfolding of all things. Another way of formulating the proposition is to say that fear grows from a demonstrative belief in the self alone, divorced from the rest of the cosmos. By shedding this fear, a “sage” can also necessarily depart from his delusions and sorrows.
The Isha Upanishad, although one of the shortest Upanishads, also advises against both “action” and “knowledge,” for both lead down a path to deeper darkness. Man is positioned at a great abyss -transience leads man into darkness, and knowledge and action lead man into an even greater darkness. However, curiously by knowing both, a sage can overcome death and reach immortality.
The Upanishad closes with a prayer to the spirit or god to “reveal” the hidden truth, and to the sun containing the sacred word “OM”, and a plea to shed the body so that it may become ashes in favor of remembrance of “past strivings.” As the scripture concludes, the author longs to follow the path of the good.
For this reading I used the Penguin Classics Edition translated by Juan Mascaro.