Mahabharata 1.44.7

1.44.7

durvāsatāṃ viditvā ca bhartuste'titapasvinaḥ |
nainamanvāgamiṣyāmi kadāciddhi śapetsa mām || 7 ||

"And he said, 'Thou knowest, 'O amiable one, the purpose of thy bestowal, the reason thereof. If, from that union, for the welfare of the snakes, a son be born, then he, possessed of energy, will save us all from the snake-sacrifice. The Grandsire had said so, of old, in the midst of the gods. O fortunate one, hast thou conceived from thy union with that best of Rishis? My heart's desire is that my bestowal of thee on that wise one may not be fruitless. Truly, it is not proper for me to ask thee about this. But from the gravity of the interests I ask thee this. Knowing also the obstinacy of thy lord, ever engaged in severe penances, I shall not follow him, for he may curse me. Tell me in detail all that thy lord, O amiable one, hath done, and extract that terribly afflicting dart that lies implanted for a long time past in my heart.'