Vidura is sent to invite the Pandavas to Hastinapura. Vyasa says Vidura comes to meet the Pandavas. Why does he not say that Vidura ‘goes’ to meet the Pandavas? The reason is because Krishna is with the Pandavas, and so Vidura will be in the right place when he meets the Pandavas. Similarly, in the Ramayana, Valmiki says that Vibhishana, expelled by Ravana, ‘comes’ to Rama. He does not say Vibhishana ‘goes’ to Rama, because it is proper and natural for a virtuous man to be beside the Lord than elsewhere. Virtuous men will naturally want to be beside the Lord.
Vidura is chosen to be Dhritarashtra’s messenger because of his diplomacy, said V.S. Karunakarachariar, in a discourse. Vidura, upon meeting King Drupada, says that Drona sends him his enquiries with his warm embraces. There is a reason for why Vidura mentions Drona. Drupada and Drona had been classmates, and Drupada had promised Drona half his kingdom when he inherited it. Drona does not ask Drupada to keep his promise, but when he approaches Drupada for help to alleviate his poverty, Drupada pretends that he does not know Drona.
Drona then vows revenge. He trains the Kuru princes and then asks Arjuna to imprison Drupada, which Arjuna easily does. Humiliated, Drupada wants revenge too. He performs a yaga, and Draupadi and Dhrishtadyumna are born as a result. Dhrishtadyumna is destined to kill Drona.
With so much ill feeling between Drona and Drupada, Vidura has a difficult task talking to Drupada, but he handles it cleverly. He also utters a white lie, when he says that Dhritarashtra is happy for the Pandavas. He humbly requests Drupada to send the Pandavas to Hastinapura. Vidura’s diplomacy pays off and the Pandavas return to Hastinapura.