2. Atharvaśira Upaniṣad on Brahman

[...] Atharvaśira Upaniṣad verse 61

Rudra is one and only one. There is none second to him. He rules all worlds by his power. He pervades fully in all beings. He is the one who, at the time of deluge, absorbs all beings. He is the one who creates all beings and upkeeps them. He alone exists, in all organs where birth takes place. He travels among all beings and is the reason for their existence. The seeker would get immeasurable peace by searching and surrendering to this god, who gives everything to the one who asks and who is praiseworthy. He converts fire, air, water, earth, ether and everything that exists here in to ash. He who sees this and mentally realizes it and observes the “penance to Paśupati (Lord of all beings)” and who coats ash all over his body with this ash attains the state of Brahman. By worshipping “Paśupati (lord of all beings)” like this, the ties of bondage of all beings get cut and they attain salvation. There is none greater than him, on whom all the worlds are strung like beads. Over ages, nothing so far where greater than him and nothing is going to be greater than him. He has thousands of legs but one and only one head. He pervades every where.

From “Akṣara (letter/language/ the deathless being)” time is created. From “time (ages) the “all pervasiveness” is created. This “all pervasiveness” is Rudra. Rudra destroys beings even when he is sleeping. From his “breath” is produced the “power of Tamas (darkness)”. From Tamas is created water. Mixing this water with finger makes it cold. By mixing the coolness the “foam” is produced. From that foam, the galaxy is produced. From the galaxy, Brahmam is produced. From Brahmam, air is produced. From air, “the sound of Om” is produced. From “the sound of Om”, Savitri is produced. From Savitri, Gāyatri is produced and from Gāyatri, all the worlds are produced. They who worship “penance” and “truth”, get permanent happiness.Worshipping that Brahmam, which is the mixture of light, water, essence and nectar, by chanting “Om Bhūr bhuva svarom” is the greatest penance.^[1]