The Upanishads are Sanskrit spiritual texts that are part of the foundation of the philosophical school called Vedanta.

In this body, in this town of Spirit, there is a little house shaped like a lotus, and in that house there is a little space. One should know what is there.

What is there? Why is it so important?

There is as much in that little space within the heart, as there is in the whole world outside. Heaven, earth, fire, wind, sun, moon, lightning, stars, whatever is and whatever is not, everything is there.

Translation Shree Purohit Swami and W. B. Yeats