Srimad Bhagavatam Canto 01, Chapter 13, Text 14

SB 1.13.14

kañcit kalam athavatsit
sat-krto devavat sukham
bhratur jyesthasya sreyas-krt
sarvesam sukham avahan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Thus Mahatma Vidura, being treated just like a godly person by his kinsmen, remained there for a certain period just to rectify the mentality of his eldest brother and in this way bring happiness to all the others.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Saintly persons like Vidura must be treated as well as a denizen from heaven. In those days denizens of heavenly planets used to visit homes like that of Maharaja Yudhisthira, and sometimes persons like Arjuna and others used to visit higher planets. Narada is a spaceman who can travel unrestrictedly, not only within the material universes but also in the spiritual universes. Even Narada used to visit the palace of Maharaja Yudhisthira and what to speak of other celestial demigods. It is only the spiritual culture of the people concerned that makes interplanetary travel possible, even in the present body. Maharaja Yudhisthira therefore received Vidura in the manner of reception offered to the demigods.
Mahatma Vidura had already adopted the renounced order of life, and therefore he did not return to his paternal palace to enjoy some material comforts. He accepted out of his own mercy what was offered to him by Maharaja Yudhisthira, but the purpose of living in the palace was to deliver his elder brother, Dhrtarastra, who was too much materially attached. Dhrtarastra lost all his state and descendants in the fight with Maharaja Yudhisthira, and still, due to his sense of helplessness, he did not feel ashamed to accept the charity and hospitality of Maharaja Yudhisthira. On the part of Maharaja Yudhisthira, it was quite in order to maintain his uncle in a befitting manner, but acceptance of such magnanimous hospitality by Dhrtarastra was not at all desirable. He accepted it because he thought that there was no alternative. Vidura particularly came to enlighten Dhrtarastra and to give him a lift to the higher status of spiritual cognition. It is the duty of enlightened souls to deliver the fallen ones, and Vidura came for that reason. But talks of spiritual enlightenment are so refreshing that while instructing Dhrtarastra, Vidura attracted the attention of all the members of the family, and all of them took pleasure in hearing him patiently. This is the way of spiritual realization. The message should be heard attentively, and if spoken by a realized soul, it will act on the dormant heart of the conditioned soul. And by continuously hearing, one can attain the perfect stage of self-realization.
Srimad Bhagavatam Canto 01, Chapter 13, Text 13
Srimad Bhagavatam Canto 01, Chapter 13, Text 15