Mbh 15.19.1a

"Vaisampayana said. 'Following the advice of Vidura, the king took up his abode on the banks of the Bhagirathi which were sacred and deserved to be peopled with the righteous. There many Brahmanas who had taken up their abode in the woods, as also many Kshatriyas and Vaisyas and Sudras, came to see the old monarch. Sitting in their midst, he gladdened them all by his words. Having duly worshipped the Brahmanas with their disciples, he dismissed them all. As evening came, the king, and Gandhari of great fame, both descended into the stream of the Bhagirathi and duly performed their ablutions for purifying themselves. The king and the queen, and Vidura and others, O Bharata, having bathed in the sacred stream, performed the usual rites of religion. After the king had purified himself by a bath, the daughter of Kuntibhoja gently led both him, who was to her as her father-in-law and Gandhari from the water into the dry bank. The Yajakas had made a sacrificial altar there for the king. Devoted to truth, the latter poured libations then on the fire. From the banks of the Bhagirathi the old king, with his followers, observant of vows and with senses restrained, then proceeded to Kurukshetra. Possessed of great intelligence, the king arrived at the retreat of the royal sage Satayupa of great wisdom and had an interview with him. Satayupa, O scorcher of foes, had been the great king of the Kekayas. Having made over the sovereignty of his kingdom to his son he had come into the woods. Satayupa, received king Dhritarashtra with due rites. Accompanied by him, the latter proceeded to the retreat of Vyasa. Arrived at Vyasa's retreat, the delighter of the Kurus received his initiation into the forest mode of life. Returning he took up his abode in the retreat of Satayupa. The high-souled Satayupa, instructed Dhritarashtra in all the rites of the forest mode, at the command of Vyasa.