Mahabharata 1.91.16

1.91.16

vasava ūcuḥ |
pratīpasya suto rājā śaṃtanurnāma dhārmikaḥ |
bhavitā mānuṣe loke sa naḥ kartā bhaviṣyati || 16 ||

"The Vasus replied, 'On earth, unto Pratipa shall be born a son, Santanu, who will be a king of world-wide fame.' Ganga then said, 'Ye celestials, that is exactly my wish which ye sinless ones have expressed. I shall, indeed, do good to that Santanu. That is also your desire as just expressed.' The Vasus then said, 'It behoveth thee to throw thy children after birth, into the water, so that, O thou of three courses (celestial, terrestrial, and subterranean) we may be rescued soon without having to live on earth for any length of time.' Ganga then answered, 'I shall do what ye desire. But in order that his intercourse with me may not be entirely fruitless, provide ye that one son at least may live.' The Vasus then replied, 'We shall each contribute an eighth part of our respective energies With the sum thereof, thou shall have one son according to thy and his wishes. But this son shall not begat any children on earth. Therefore, that son of thine endued with great energy, shall be childless.'