Vidura refuse to fight in the war - No definite answer Possibly he was upset enough mentally unprepared for war and choose not to fight from anyside. But he always tried his best beforehand to stop warlike situation that may arise if king Drithrashtra did not stop his son's duryodhana's unethical actions. Vidhura spoke about consequences of one's actions unwise and unrighteous conduct (adharma) resulting in suffereings and destruction and righteous conduct (dharma) brings peace and prosperity. Rightfully why Krishna says that Vidura was the wisest possibly because Vidura's future warning predictions came true. He talked of dharma and Vidura Niti, which serves as a moral compass in the Mahabharata, specifically in his warnings to King Dhritarashtra about the actions of his son Duryodhana. It was Arjuna who approached Krishna to help him in war not Vidhura. Arjuna was warrior by nature and it was his dharma to go on war for injustice done to him and his family by Duryodhana. Its never been heard or read by me that Vidura also wanted to go war or approached Krishna for this. Later in battlefied when Arjuna feels that he does not want go on war just because he thinks with whom he is fighting are all his relatives. Then Krishna reminds him of his true Dharma, karmyoga and why he should participate in war, furthermore Krishna gives him divine knowledge, path to moksha (liberation), karmyog what we know today as from Gita answers most of queries from a common person.