Isa upanishad

 The Isha Upanishad (Sanskrit: ईशोपनिषद्, IAST: Īśopaniṣad), also known as Shri Ishopanishad, Ishavasya Upanishad, or Vajasaneyi Samhita Upanishad, is one of the shortest Upanishads, embedded as the final chapter (adhyāya) of the Shukla Yajurveda. It is a Mukhya (primary, principal) Upanishad,

 The Upanishad is a brief poem, consisting of 17 or 18 verses, depending on the recension.

The name of the text derives from its incipit, īśā vāsyam, "enveloped by the Lord",or "hidden in the Lord (Self)".

The text discusses the Atman (Self) theory of Hinduism.

Adi Shankara, in his Bhasya (review and commentary) noted that the mantras and hymns of Isha Upanishad are not used in rituals, because their purpose is to enlighten the reader as to "what is the nature of Self (Atman)?";

Enveloped by the Lord must be This All — each thing that moves on earth. With that renounced, enjoy thyself. Covet no wealth of any man.

— Isha Upanishad, Hymn 1[20]

in hymns 2–6, the Upanishad acknowledges the contrasting tension between the empirical life of householder and action (karma) and the spiritual life of renunciation and knowledge (jnana).

Should one wish to live a hundred years on this earth, he should live doing Karma. 

While (thus, as man,) you live, there is no way other than this by which Karma will not cling to you. 

Those who partake the nature of the Asuras [evil], are enveloped in blind darkness, and that is where they (also) reside who ignore their Atman [Self]. 

For liberation, know your Atman, which is motionless yet faster than mind, it is distant, it is near, it is within all, it is without all this. It is all pervading. 

he who beholds all beings in the Self, and the Self in all beings, he never turns away from it [the Self].

— Isha Upanishad, Hymns 2-6[18]

The Isha Upanishad suggests that one root of sorrow and suffering is considering one's Self as distinct and conflicted with the Self of others, assuming that the nature of existence is a conflicted duality where one's happiness and suffering is viewed as different from another living being's happiness and suffering. Such sorrow and suffering cannot exist, suggests the Upanishad, if an individual realizes that the Self is in all things, understands the Oneness in all of existence, focuses beyond individual egos and in the pursuit of Universal values, the Self and Real Knowledge

The hymns 12 through 14 of Isha Upanishad, caution against the pursuit of only manifested cause or only spiritual cause of anything, stating that one sided pursuits lead to darkness. To be enlightened, seek both (उभय सह, ubhayam saha), suggests the Upanishad.It asserts that he who knows both the Real and the Perishable, both the manifested not-True cause and the hidden True cause, is the one who is liberated unto immortality

In final hymns 15 through 18, the Upanishad asserts a longing for Knowledge, asserting that it is hidden behind the golden disc of light, but a light that one seeks. It reminds one's own mind to remember one's deeds, and accept its consequences.[18] The Madhyandina recension and Kanva recension vary in relative sequencing of the hymns, but both assert the introspective precept, "O Agni (fire) and mind, lead me towards a life of virtues, guide me away from a life of vices", and thus unto the good path and the enjoyment of wealth (of both karma's honey and Self-realization).[19][22] The final hymns of Isha Upanishad also declare the foundational premise, "I am He", equating one Self's oneness with cosmic Self.[18][30]

पुरुषः सोऽहमस्मि

I am He, the Purusha within thee.

— Isha Upanishad, Hymn 16 Abridged[25]