Mahabharata 1.2.212

1.2.212

tata āśramavāsākyaṃ parva pañcadaśaṃ smṛtam |
yatra rājyaṃ parityajya gāndhārīsahito nṛpaḥ |
dhṛtarāṣṭrāśramapadaṃ viduraśca jagāma ha || 212 ||

"Then comes the fifteenth Parva called Asramvasika. In this, Dhritarashtra, abdicating the kingdom, and accompanied by Gandhari and Vidura went to the woods. Seeing this, the virtuous Pritha also, ever engaged in cherishing her superiors, leaving the court of her sons, followed the old couple. In this is described the wonderful meeting through the kindness of Vyasa of the king (Dhritarashtra) with the spirits of his slain children, grand-children, and other princes, returned from the other world. Then the monarch abandoning his sorrows acquired with his wife the highest fruit of his meritorious actions. In this Parva, Vidura after having leaned on virtue all his life attaineth to the most meritorious state.