The Isha ("Lord") Upanishad is a Hindu scripture.
One of the smallest of the early theoretical manuscripts
known as the Upanishads, with just eighteen lines; the title derives from the
first word of the text.
Due to its shortness, creation in poetry rather than prose,
and usage of poems from other upanishads, it is thought to be one of the late
upanishads.
The Isha Upanishad, like many later upanishads, proposes a
loosely defined monism, in which all phenomena are attributed to a single
force.
This power may be found by a flash of mystic insight, in
which the seeker is able to see through the illusion that items are interconnected
and perceive the universe's one true force.
The insight is said to provide a comprehensive understanding of the workings of the cosmos, as well as the individual's ultimate liberation from the cycle of rebirth (moksha) (samsara).
You may also want to read more about Hinduism here.
Be sure to check out my writings on religion here.