Chapter 38 of 76 · Vayaviya Samhita · Overall chapter 426 of 464
Shiva's Forms
Upamanyu lays out Shiva's two foundational five-and-eight-fold schemes - the five brahmanas (Ishana, Purusha, Aghora, Vamadeva, Sadyojata) presiding respectively over the senses, and the eight forms (Sharva, Bhava, Rudra, Ugra, Bhima, Pashupati, Ishana, Mahadeva) presiding over the elements, sun and moon - as the structural basis by which Shiva's single atman pervades the entire universe.
Upamanyu said
Listen, Krishna. Mahesha Shiva is the supreme self, and all that is, whether it moves or stands still, is filled by forms of his own being. Through these forms Shiva is present in everything, even though his self cannot be measured; he is said to rule over it all. The forms that fill the universe are Brahma, Vishnu, Rudra, Mahesha and Sadashiva. He also has the five brahmana forms, and nothing escapes their pervasion. These five are Ishana, Purusha, Aghora, Vamadeva and Sadyojata. Ishana is the first and highest. He enjoys Prakriti and abides as the knower of the field. Lord Sthanu himself is unmanifest; his manifest form is Purusha, who takes up the gunas and presides over the unmanifest that is enjoyed. The bearer of the Pinaka has the much-worshipped form of Aghora, who rules the principle of intelligence and the eight divisions beginning with dharma. Those who know the rulerships say Vamadeva presides over the ego, and Sadyojata, form of the boundlessly radiant Shambhu, over the mind.
Ishana, they teach, governs hearing, speech, sound and space. Purusha governs the skin, the hands, touch and air, as those who know the Puranas affirm. Aghora governs the eyes, the feet, colour and fire. Vamadeva governs the tongue, the organ of excretion, taste and water. Sadyojata governs the nose, the organ of generation, smell and earth. These five forms are the sole sources of well-being, so whoever wants welfare should keep on worshipping them. He is the first lord of the gods, and his eight forms run through the universe like jewels on a string: Sharva, Bhava, Rudra, Ugra, Bhima, Pashupati, Ishana and Mahadeva. They rule earth, water, fire, air, space, the knower of the field, the sun and the moon, in that order. As Vishvambhara he bears the universe and everything in it, which is what the scriptures fix as Sharva's auspicious form. The form that gives life to all as water is called Bhava. The form that fills the world inside and out as sacred fire is called Rudra, fierce and terrible. The form in the wind, which trembles and sets all things trembling, frightening yet virtuous, is Ugra. Bhima is the dreadful form that splits the elements, spreads as space and makes room for everything. Pashupati dwells in every body as the ruler of every self and unties the Pashus from their bonds. The form that is the sun and lights the universe is Ishana, who travels the sky. The form that is the moon and feeds the world with amrita rays is Mahadeva.
Shiva, the supreme self, draws these eight forms out of himself and fills the other forms as well. So the universe has him for its self. Water the root of a tree and the branches thrive; worship Shiva and the universe, which is his body, thrives with him. The learned know that when Shiva is worshipped he removes fear and shows favour to all. As a father is glad when his children and grandchildren are glad, so Shankara is glad when all are glad. If someone acts to cramp any embodied creature, doubtless it is the same as hurting Shiva's eight forms, since in them his self is established throughout the universe. So worship Rudra, the highest cause, with every possible feeling.
Retold in our own words from Bibek Debroy's English translation of the Shiva Purana (Penguin Classics). Names, numbers and the order of events follow the source.