The Isha Upanishad is unique in two senses. It is a very short Upanishad, consisting of only eighteen shlokas or verses. It is also the only Upanishad that forms part of the last chapter of the Shukla Yajur Veda. It is known as the text is isha, which means, by the supreme godhead. The motif of the Upanishad is, someone who knows the identity of the human soul with the divine soul is learned. In contrast, an individual who lacks this knowledge is ignorant. The text is composed entirely in verse.
Every object in the universe is transient. And all such objects are encompassed by the supreme godhead. Give up all these transient objects and look to the eternal. Do not lust for the wealth of others. Wealth belongs to no one.
He who desire to live on this earth for a hundred years, pursues the path of action (Karma). There is no other prescribed path for one who aspires for a long life. Deviation from this norm leads one to tread the path of sin.
The worlds where the demons (asuras) dwell, are shrouded in impenetrable darkness. Individuals who commit suicide are destined for those worlds after their deaths.