Abdullah bin Wahb narrates: (Allamah Haythami says:) I say: the correct name is "Abdullah bin Mawhab". He narrates: "Once Sayyiduna Uthman (may Allah be pleased with him) said to Sayyiduna Abdullah bin Umar (may Allah be pleased with them both): 'Take up the office of judge.' Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: 'O Commander of the Believers, will you not excuse me?' Sayyiduna Uthman (may Allah be pleased with him) said: 'Go and judge between the people as a judge.' Sayyiduna Abdullah (may Allah be pleased with him) said: 'O Commander of the Believers, will you not excuse me?' Sayyiduna Uthman (may Allah be pleased with him) said: 'I insist upon you that you go and give judgements.' Sayyiduna Abdullah (may Allah be pleased with him) said: 'Do not be hasty. I heard the Prophet (peace and blessings be upon him) say: "Whoever seeks refuge with Allah Almighty has sought a mighty refuge."' Sayyiduna Uthman (may Allah be pleased with him) said: 'Very well.' Sayyiduna Abdullah (may Allah be pleased with him) said: 'Then I seek refuge with Allah from becoming a judge.' Sayyiduna Uthman (may Allah be pleased with him) asked: 'What prevents you, when your father used to give judgements as a judge?' Sayyiduna Abdullah (may Allah be pleased with him) replied: 'Because I heard the Prophet (peace and blessings be upon him) say: "Whoever is a judge and judges between the people with injustice will be among the people of Hell; whoever is a judge and judges in ignorance will be among the people of Hell; and whoever is a judge who is also knowledgeable, and judges according to the truth (the narrator is in doubt, or perhaps the words are:) according to justice, will ask to be let off even."'"
(Allamah Haythami says:) I say: Tirmidhi has recorded part of this report.
Abu Ya'la recorded it in al-Kabir, and its narrators are thiqat (trustworthy), except that in the case of Abdullah bin Mawhab I have not found any report of his having heard from Sayyiduna Uthman (may Allah be pleased with him).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 17170