Skandapurana 6.2.71.75

Īśvara said:
Know the seventy-first to be called Prayāgeśvara; / know it to be incomparable, destroying heinous sins. (1)
In the city of Hāstina there was a fortunate and supreme king, Śaṃtanu, / in the Vaivasvata interval of the kalpa, during the age called Dvāpara. (2)
He possessed wondrous great prowess, a youth of adamantine build, / skilled in all sacred sciences, knowledgeable in the host of arts, (3)
equal to Viṣṇu in strength, and like the sun in splendour. / He wandered alone along the Gaṅgā, which is frequented by siddhas and cāraṇas. (4)
Once that mighty-armed king, possessing abundant troops and mounts, / entered the dense forest surrounded by hundreds of horses and elephants. (5)
Having gone there, the best of kings killed deer and tigers sportively, / striking down buffaloes, wild horses, and boars. (6)
Once in that forest he saw a superb woman / blazing with her body, just like a visible second Padmā. (7)
Seeing her, his hair stood on end, amazed by her wealth of beauty; / as if drinking her in with both eyes, the lord of men was not satiated. (8)
And as soon as she saw the king of great splendour roaming about, / that charming woman, filled with love and affection, was not satiated. (9)
Then the king addressed her, soothing her with gentle words: / "Are you a goddess, a Dānavī, a Gandharvī, or an apsaras, (10)
or a Yakṣī, a serpent maiden, or a human woman, O slender-waisted lady? / I beseech you who resemble the interior of a lotus: become my wife, O beautiful one!" (11)
Having heard these words of the king, praised, soft, and lovely, / it was accepted by her, O goddess, and a stipulation was requested of the king: (12)
"If I am prevented or treated with displeasure, I shall certainly abandon you. / You must never ask, O king: 'Who are you and whose are you?'" (13)
"So be it," said he, with truthfulness and virtue. / By her conduct and character, her beauty, generosity, and virtues, (14)
and by her attentions in private, the lord of the earth was delighted. / For she was of divine form, the goddess Gaṅgā, the river flowing along three paths. (15)

Having assumed a human form, radiant one, O lady of excellent complexion, / she brought delight to the king, and took delight in him as well. (16)
Attached to amorous pleasure and captivated by the excellent qualities of women, / the king did not notice the passing of many years, seasons, and months. (17)
Sporting with her at his pleasure, the ruler of men / begot upon her eight sons who possessed immortal complexion. (18)
As each son was born, she threw him into the water for his liberation, / saying, "I please you," into the purifying current of the Gaṅgā. (19)
That was not pleasing to King Śaṃtanu at all; / yet the lord of the earth said nothing to that goddess, terrified of abandonment. (20)
Then, as the eighth son was born and she seemed to smile, / the king, afflicted with grief and wishing to protect his son, said: (21)
"Do not kill him! Whose are you and who are you? Why do you destroy your sons? / Slaying a son is a great sin; do not incur it, stay, O blameworthy woman!" (22)
Gaṅgā said:
"O best of those who have sons, desiring a son as you do, I shall not kill your son. / But my stay here has come to an end, according to the agreement made by me. (23)
I am Gaṅgā, the daughter of Jahnu, attended by hosts of great seers; / I have dwelt with you for the sake of accomplishing the purpose of the gods. (24)
These are the eight Vasu gods, very terrible and of great splendour; / by the flaw of Vasiṣṭha's curse they entered into human state. (25)
Other than you, no bringer of them exists on the earth, / and a human mother such as I could never exist. (26)
Therefore, for the sake of being their mother, I have assumed human state. / May welfare be yours; I shall depart. Protect your son, O king of great vows!" (27)
Having spoken thus, Gaṅgā, deluded by the māyā of Viṣṇu, / wept, having resorted to human nature, that slender-waisted lady: (28)
"Oh, alas, what great misery that these sons were killed! / By me, cruel through delusion, the infants were cast into the water. (29)
Alas, my children! Alas, my sons! Where indeed are my dear boys?"

"Where have they gone, leaving me? Why does my heart not burst? / Calling out plaintively, 'Mother! Mother!', coming of their own accord, / when, embracing those sons in affection, crying, 'My child! My child!'— / by whom, coated with tawny dust of the earth, / will my upper garment and lap ever be soiled? / Born from each and every limb, delighting mind and heart, / alas, my children have been killed, sent to death by me, their mother! / What worlds shall I go to after committing such a dreadful deed? / How shall I, a merciless slayer of sons, ever become pure?" / Lameneting piteously thus, weeping again and again, / she fainted and fell to the ground, distressed and motionless. / In the meantime, O goddess, Nārada, the best of sages, / suddenly heard that sound of her lamentation. / With eyes wide with wonder, he thought: "What is this? / This is that Gaṅgā, born of Jahnu, purifier, praised by the gods, / the divine chief queen of the ocean, the sacred three-pathed river; / having assumed human nature, why does she weep so wildly?" / Thinking thus, the sage approached; / Nārada, the son of Brahmā, standing in the sky, said loudly to the weeping Gaṅgā: / "O goddess Gaṅgā, obeisance to you! / I am Nārada, O most holy one. Why do you weep, O purifier? / You are renowned as the daughter of the snowy mountain, attended by gods and gandharvas, / borne on the head by the god Śiva, the Supreme Lord." / Hearing Nārada's words, the divine river of the gods, / beholding him situated in his aerial chariot, replied to the great sage: / "O Nārada, through delusion I have committed a reprehensible unrighteousness; / knowing full well it was a great sin, seven sons were killed by me. / Separation from the ocean befell me by fate; / I became the wife of a mortal; sons were born to me and were slain. / Therefore I lament, submerged in an ocean of grief.

Tell me, O divine seer, how I may indeed become pure." / Hearing these words of hers, Nārada, the best of sages, / who knows the three times and is pure-souled, spoke to Gaṅgā: / Nārada said: / "O you praised by the world, have you forgotten the auspicious agreement with the gods, / which was promised by you, O goddess, for the liberation of the Vasus? / Those Vasus have attained their realms by your grace, O faithful one! / The ocean, called Śaṃtanu, was brought down [to earth] by you, O goddess." / Hearing these words of the noble Nārada, / holy Gaṅgā, the three-pathed river, replied to the great sage: / "You have spoken the truth, O brahmin; now I know everything. / But because a human womb was taken, I was bewildered by it. / Terrified of the fear of infamy, I have taken refuge in you. / Give me instruction; tell me of an excellent place." / Nārada said: / "O you praised by the world, is the agreement made with the gods forgotten? / If, terrified of the fear of infamy, O goddess who bestows merit, / you ask me for an ultimate place, listen, O faithful one, I shall tell you. / Avantī is renowned, eternal through seven kalpas; / in it is your friend Śiprā, who is always dear to brahmins. / On its bank, to the south of Durdharṣeśvara, is an auspicious liṅga, / worthy of worship by the thirty [gods] and attended by all sacred fords. / Merely by its darśana, you will have accomplished your purpose. / Therefore, go, O most holy Gaṅgā, attended by divine seers!" / Thus addressed by the noble Nārada, the most holy three-pathed river / went there and beheld her friend Śiprā. / Then, embracing her and beholding the supremely purifying liṅga, / she worshipped it with devotion and remained right there for a long time. / Then the goddess Yamunā, daughter of the sun, destroyer of sin, / came there with affection to where Gaṅgā was staying.

The goddess beheld Gaṅgā meditating on Śiva, Śaṃkara. / She too remained right there, worshipping supreme Śiva. / Then, at that very time, goddess Sarasvatī, flowing eastward, / arrived, deeply concealed, in the waters of Gaṅgā and Yamunā. / Meanwhile, O goddess, Nārada said to Śakra: / "Prayāga is not seen; it has gone to the forest of Mahākāla. / Where Sarasvatī is concealed between Gaṅgā and Yamunā, / that is to be known as Prayāga, destroyer of all sins. / That Prayāga is now in the excellent forest of Mahākāla; / for what reason it has gone, I do not know." / Hearing these words of the noble Nārada, / all [the gods], accompanied by Śakra, came to Avantī, / praising the auspicious, three-pathed Gaṅgā with various hymns: / "O goddess Gaṅgā, obeisance to you, destroyer of all sins, / mother of the Vasus, O goddess, granter of liberation to the Vasus, / ever the purifier of the three worlds, borne on the head by Hara! / Attended by the Vālakhilyas, the supreme part of Kṛṣṇa, / O Yamunā, Kālindī, river of boons, we bow to you! / You are the purifying daughter of Mārtaṇḍa, lord of the sky. / O goddess Śiprā, born from the body of Brahmā, auspicious one, obeisance to you! / You alone are renowned as the eastward-flowing Sarasvatī of holy form; / that which flows eastward in the sacred field of the Kurus, at Puṣkara, and at Mahālaya, / you, that very same renowned Śiprā, are the destroyer of all wicked deeds. / You are compassion to all beings, heaven, and refuge to mortals; / you are the mother of all beings; you are sung on earth as the eastward-flowing. / Seeing the stain and mark of many births of embodied beings on earth, / you wash it away, O goddess; such are you, abiding in the three worlds. / The confluence of these [rivers] is remembered by the wise as Prayāga. / Having arrived here, it is now established and bathed by you."

From today onward, this god named Prayāgeśvara / shall be renowned throughout the three worlds, destroying sins by merely being remembered. / Those who come here and behold Prayāgeśvara thereafter / shall attain their goal, freed from all sins. / Their ancestral lines, both paternal and maternal, will be saved; / the three yugas' merit of the Gaṅgā, granting the fruit of the four goals of life, / arises from the darśana of Prayāgeśvara—of this there is no doubt.