Prasna Upanishad consists of six questions (prasnas) and their answers. It is also associated with the Atharva Veda
Six students (Sukesha, Satyakama, Sauryayanee, Bhargava, Kabandhi) interested in knowing divinity or Brahman come to sage Pippalada and request him to clarify their spiritual doubts.
The fourth question asked by Souryayanee Gargya is concerned with dreams world of human beings.
Sauryayanee Gargya asks
“atha hEnam souryayanee gargya papraccha |
bhagavannEtasmin purushE kaani svapanti kaanyasmin jaagrati katar yEsha dEva |
swapnaan pashyati kasyaitata sukham bhavati kasminnu sarvE sampratishTitaa bhavanteeti |”
Translation : Sauryayani, belonging to the family of Garga, asked: “Sir, what are they that sleep in man and what are they that remain awake in him ? Which deity is it that sees dreams ? Whose is the happiness ? In whom, again, are all these gathered together ?”
Sage Pippalada replied “O Gargya, As all the rays of the sun, when it sets, are gathered up in that disc of light, and as they, when the sun rises again and again, come forth, so is all this (all the senses) gathered up in the highest faculty (deva), the mind. Therefore at that time that man does not hear, see, smell, taste, touch, he does not speak, he does not take, does not enjoy, does not evacuate, does not move about. He sleeps, that is what People say.
The prana fires remain awake in this city (body) during sleep/dream. Apana is the Garhapatya Fire and vyana, the Anvaharyapachana Fire. And prana is the Ahavaniya Fire, so called from being taken—since it is taken from the Garhapatya Fire.
Samana is so called because it distributes equally the two oblations, namely, the out—breathing and the in—breathing; it is the priest. The mind, verily, is the sacrificer. Udana is the fruit of the sacrifice, because it leads the sacrificer every day, in deep sleep, to Brahman.
There, in dreams, that god, the mind, experiences glory. Whatever has been seen he sees again; whatever has been heard he hears again; whatever has been experienced in different countries and quarters, he experiences again. Whatever has been seen or not seen, heard or not heard and whatever is real or not real—he sees it all. He sees all, himself being all.
When the jiva is overcome by light he sees no dreams; at that time, in this body, arises this happiness.
As a bird goes to a tree to roost, even so, O friend, all this rests in the Supreme Atman : Earth and its subtle counterpart, water and its subtle counterpart, fire and its subtle counterpart, air and its subtle counterpart, akasa and its subtle counterpart, the eye and what can be seen, the ear and what can be heard, the nose and what can be smelt, the taste and what can be tasted, the skin and what can be touched, the organ of speech and what can be spoken, the hands and what can be grasped, the organ of generation and what can be enjoyed, the organ of excretion and what can be excreted, the feet and what is their destination, the mind (manas) and what can be thought, the intellect (buddhi) and what can be comprehended, the ego (ahamkara) and the object of egoism, the memory (chitta) and its object, knowledge (tejah) and its object, prana and what is to be supported.
He, verily, it is who sees, feels, hears, smells, tastes, thinks and knows. He is the doer, the intelligent self, the purusha. He is established in the Highest, the imperishable Atman.
He who knows that indestructible being, obtains (what is) the highest and indestructible, he without a shadow, without a body, without colour, bright,yes, O friend, he who knows it, becomes all-knowing, becomes all.
He, who knows that indestructible being wherein the true knower, the vital spirits (pranas), together with all the powers (deva), and the elements rest, he, being all-knowing, has penetrated all.”
Thus, it can be understood that humans and other living beings live like Brahma, the creator.
They absorb everything into themselves during sleep and when they wakeup, they re-create everything including themselves.
The supreme god exists in all of us, making us go through the process of creation and absorption everyday.