Vishnu's Vishwarupa form, AKA his Sahasrashirsha or Aniruddha form, is described in many different places in Hindu scripture:
- The earliest reference to Vishnu's Vishwarupa is the Purusha Sukta, a hymn from the Rig Veda:
- A thousand heads hath Puruṣa, a thousand eyes, a thousand feet.
On every side pervading earth he fills a space ten fingers wide.
- This Puruṣa is all that yet hath been and all that is to be;
The Lord of Immortality which waxes greater still by food.
- So mighty is his greatness; yea, greater than this is Puruṣa.
All creatures are one-fourth of him, three-fourths eternal life in heaven.
- With three-fourths Puruṣa went up: one-fourth of him again was here.
Thence he strode out to every side over what cats not and what cats.
- From him, Virāj was born[.]
Verse 5 is a reference to Brahma being born from Vishnu's Vishwarupa. (People often assume that it was Vishnu's four-armed form that gave birth to Brahma, but it was the Vishwarupa form that lied down at the end of the Mahapralaya on Vishnu's serpent Adiseshan.) The rest of the hymn talks about how Vishnu in his Vishwarupa form offered himself to be sacrificed in a cosmic Yagna, so Brahma could turn his body into the Universe.
I should add that the Purusha Sukta was heard from the gods by the sage Narayana, an ancient incarnation of Vishnu who found the Pancharatra movement which was influential in the development of Vaishnavism, as I discuss here.
- The Shanti Parva of the Mahabharata describes how Narada once visited the sages Nara and Narayana (the incarnation of Vishnu I discussed above), who were engaging in Tapasya in Badarikashrama. Narada asked them what god they could possibly be worshipping, given that they were such illustrious divine beings themselves. They answered that they were worshipping Vishnu, who lies at the core of their soul. So Narada proceeded Vishnu's ocean of milk to see Vishnu himself. Initially he couldn't find him, so he spontaneously composed a hymn of praise to Vishnu, and then Vishnu appeared before him in his Vishwarupa form:
Thus hymned with names that were not known to others, the Divine Narayana having the universe for his form showed himself to the ascetic Narada. His form was somewhat purer than the moon and differed from the moon in some respects. He somewhat resembled a blazing fire in complexion. The puissant Lord was somewhat of the form of Vishti. He resembled in some respects the feathers of the parrot, and in some a mass of pure crystal. He resembled in some respects a hill of antimony and in some a mass of pure gold. His complexion somewhat resembled the coral when first formed, and was somewhat white. In some respects that complexion resembled the hue of gold and in some that of the lapis lazuli. In some respects it resembled the hue of the blue lapis lazuli and in some that of sapphire. In some respects it resembled the hue of the peacock's neck, and in some that of a string of pearls. Bearing these diverse kinds of hues on his person, the eternal Deity appeared before Narada. He had a thousand eyes and was possessed of great beauty. He had a hundred heads and a hundred feet. He had a thousand stomachs and a thousand arms. He seemed to be still inconceivable to the mind. With one of his mouths he uttered the syllable Om and then the Gayatri following Om. With mind under complete control, the great Deity, called by the names of Hari and Narayana, by his other mouths, multitudinous in number, uttered many mantras from the four Vedas which are known by the name of Aranyaka. The Lord of all the deities, the great God who is adorned in sacrifices, held in his hands a sacrificial altar, a Kamandalu, few white gems, a pair of sandal, a bundle of Kusa blades, a deer-skin, a toothstick, and a little blazing fire.
By the way, I'm not sure why he was holding the objects described at the end, which is why I asked this question.
- In the Udyoga Parva of the Mahabharata, when Krishna goes to Duryodhana's court as an envoy of the Pandavas, Duryodhana tries to imprison Krishna. So Krishna reveals his Vishwarupa form to everyone in the court, to show the Kauravas what they're up against if they choose to go to war with the Pandavas:
Kesava, that slayer of hostile divisions, endued with great energy, addressed Dhritarashtra's son, Duryodhana, and said, "From delusion, O Suyodhana, thou regardest me to be alone, and it is for this, O thou of little understanding, that thou seekest to make me a captive after vanquishing me by violence. Here, however, are all the Pandavas and all the Vrishnis and Andhakas. Here are all the Adityas, the Rudras, and the Vasus, with all the great Rishis." Saying this Kesava, that slayer of hostile heroes burst out into a loud laughter.
And as the high-souled Sauri laughed, from his body, that resembled a blazing fire, issued myriads of gods, each of lightning effulgence, and not bigger than the thumb. And on his forehead appeared Brahman, and on his breast Rudra. And on his arms appeared the regents of the world, and from his mouth issued Agni, the Adityas, the Sadhyas, the Vasus, the Aswins, the Marutas, with Indra, and the Viswedevas. And myriads of Yakshas, and the Gandharvas, and Rakshasas also, of the same measure and form, issued thence. And from his two arms issued Sankarshana and Dhananjaya. And Arjuna stood on his right, bow in hand, and Rama stood on his left, armed with the plough. And behind him stood Bhima, and Yudhishthira, and the two sons of Madri, and before him were all the Andhakas and the Vrishnis with Pradyumna and other chiefs bearing mighty weapons upraised. And on his diverse arms were seen the conch, the discus, the mace, the bow called Saranga, the plough, the javelin, the Nandaka, and every other weapon, all shining with effulgence, and upraised for striking. And from his eyes and nose and ears and every part of his body, issued fierce sparks of fire mixed with smoke. And from the pores of his body issued sparks of fire like unto the rays of the sun. And beholding that awful form of the high-souled Kesava, all the kings closed their eyes with affrighted hearts, except Drona, and Bhishma, and Vidura, endued with great intelligence, greatly blessed Sanjaya, and the Rishis, possessed of wealth of asceticism, for the divine Janardana gave unto them this divine sight on the occasion. And beholding in the (Kuru) court that highly wonderful sight, celestial drums beat (in the sky) and a floral shower fell (upon him). And the whole Earth trembled (at the time) and the oceans were agitated. And, O bull of the Bharata's race, all the denizens of the earth were filled with great wonder. Then that tiger among men, that chastiser of foes, withdrew that divine and highly wonderful, and extremely varied and auspicious form.
- Most famously, in chapter 11 of the Bhagavad Gita, after hearing Krishna describe his glorious qualities, Arjuna asks to see the form that Vishnu had in the beginning of creation (as described in the Purusha Sukta above). So Krishna gives Arjuna divine eyes to see his Vishwarupa form:
O King, having spoken thus, the Supreme Lord of all mystic power, the Personality of Godhead, displayed His universal form to Arjuna. Arjuna saw in that universal form unlimited mouths, unlimited eyes, unlimited wonderful visions. The form was decorated with many celestial ornaments and bore many divine upraised weapons. He wore celestial garlands and garments, and many divine scents were smeared over His body. All was wondrous, brilliant, unlimited, all-expanding. If hundreds of thousands of suns were to rise at once into the sky, their radiance might resemble the effulgence of the Supreme Person in that universal form. At that time Arjuna could see in the universal form of the Lord the unlimited expansions of the universe situated in one place although divided into many, many thousands. Then, bewildered and astonished, his hair standing on end, Arjuna bowed his head to offer obeisances and with folded hands began to pray to the Supreme Lord.
Arjuna said: "My dear Lord Kṛṣṇa, I see assembled in Your body all the demigods and various other living entities. I see Brahmā sitting on the lotus ﬂower, as well as Lord Śiva and all the sages and divine serpents. O Lord of the universe, O universal form, I see in Your body many, many arms, bellies, mouths and eyes, expanded everywhere, without limit. I see in You no end, no middle and no beginning. Your form is difﬁcult to see because of its glaring effulgence, spreading on all sides, like blazing ﬁre or the immeasurable radiance of the sun. Yet I see this glowing form everywhere, adorned with various crowns, clubs and discs. You are the supreme primal objective. You are the ultimate resting place of all this universe. You are inexhaustible, and You are the oldest. You are the maintainer of the eternal religion, the Personality of Godhead. This is my opinion. You are without origin, middle or end. Your glory is unlimited. You have numberless arms, and the sun and moon are Your eyes. I see You with blazing ﬁre coming forth from Your mouth, burning this entire universe by Your own radiance. Although You are one, You spread throughout the sky and the planets and all space between. O great one, seeing this wondrous and terrible form, all the planetary systems are perturbed. All the hosts of demigods are surrendering before You and entering into You. Some of them, very much afraid, are offering prayers with folded hands. Hosts of great sages and perfected beings, crying “All peace!” are praying to You by singing the Vedic hymns. All the various manifestations of Lord Śiva, the Ādityas, the Vasus, the Sādhyas, the Viśvedevas, the two Aśvīs, the Maruts, the forefathers, the Gandharvas, the Yakṣas, the Asuras and the perfected demigods are beholding You in wonder. O mighty-armed one, all the planets with their demigods are disturbed at seeing Your great form, with its many faces, eyes, arms, thighs, legs and bellies and Your many terrible teeth; and as they are disturbed, so am I. O all-pervading Viṣṇu, seeing You with Your many radiant colors touching the sky, Your gaping mouths, and Your great glowing eyes, my mind is perturbed by fear. I can no longer maintain my steadiness or equilibrium of mind. O Lord of lords, O refuge of the worlds, please be gracious to me. I cannot keep my balance seeing thus Your blazing deathlike faces and awful teeth. In all directions I am bewildered. All the sons of Dhṛtarāṣṭra, along with their allied kings, and Bhīṣma, Droṇa, Karṇa – and our chief soldiers also – are rushing into Your fearful mouths. And some I see trapped with heads smashed between Your teeth. As the many waves of the rivers ﬂow into the ocean, so do all these great warriors enter blazing into Your mouths. I see all people rushing full speed into Your mouths, as moths dash to destruction in a blazing ﬁre.
O Viṣṇu, I see You devouring all people from all sides with Your ﬂaming mouths. Covering all the universe with Your effulgence, You are manifest with terrible, scorching rays. O Lord of lords, so ﬁerce of form, please tell me who You are. I offer my obeisances unto You; please be gracious to me. You are the primal Lord. I want to know about You, for I do not know what Your mission is."
The Supreme Personality of Godhead said: "Time I am, the great destroyer of the worlds, and I have come here to destroy all people. With the exception of you [the Pāṇḍavas], all the soldiers here on both sides will be slain. Therefore get up. Prepare to ﬁght and win glory. Conquer your enemies and enjoy a ﬂourishing kingdom. They are already put to death by My arrangement, and you, O Savyasācī, can be but an instrument in the ﬁght."