The Upanishads are a collection of religious texts, written in Sanskrit and forming part of the Hindu scriptures. They were written between the 8th and 6th centuries BC, though the name Upanishad is sometimes also extended to cover many later writings on the Vedanta philosophy.
The quotations used here are taken from the translation by Max Müller, first published 1879-84.
- Know the Self to be sitting in the chariot, the body to be the chariot, the intellect (buddhi) the charioteer, and the mind the reins. The senses they call the horses, the objects of the senses their roads. When he (the Highest Self) is in union with the body, the senses, and the mind, then wise people call him the Enjoyer.
- As large as this ether (all space) is, so large is that ether within the heart. Both heaven and earth are contained within it, both fire and air, both sun and moon, both lightning and stars; and whatever there is of him (the Self) here in the world, and whatever is not (i. e. whatever has been or will be), all that is contained within it.
- This earth is the honey (madhu, the effect) of all beings, and all beings are the honey (madhu, the effect) of this earth.
- When the speech of this dead person enters into the fire, breath into the air, the eye into the sun, the mind into the moon, the hearing into space, into the earth the body, into the ether the self, into the shrubs the hairs of the body, into the trees the hairs of the head, when the blood and the seed are deposited in the water, where is then that person?
- Brihadaranyaka Upanishad, 3.2.13. 
- The gods love what is mysterious, and dislike what is evident.
- Brihadaranyaka Upanishad, 4.2.2.