Mahabharata 1.173.2

1.173.2

jānatā ca paraṃ dharmaṃ lokyaṃ tena mahātmanā |
agamyāgamanaṃ kasmādvasiṣṭhena mahātmanā |
kṛtaṃ tena purā sarvaṃ vaktumarhasi pṛcchataḥ || 2 ||

"Arjuna asked, 'What for, O Gandharva, did king Kalmashapada command his queen to go unto that foremost of all persons conversant with the Vedas--the master Vasishtha? Why also did that illustrious and great Rishi Vasishtha himself who was acquainted with every rule of morality know a woman he should not have known? O friend, was this an act of sin on the part of Vasishtha? It behoveth thee to remove the doubts I entertain and refer to thee for solution.'