Musnad Ahmad 5:163

Wahb ibn Jarir narrated to us, my father narrated to us, I heard al-A’mash narrating from ‘Amr ibn Murrah, from Abu al-Bakhtari, from ‘Ali, who said: ‘Umar ibn al-Khattab said to the people: "What is your opinion regarding the surplus of this wealth that we have?" The people said: "O Commander of the Faithful, we have kept you busy away from your family, your estate, and your trade, so it is yours." He said to me: "What do you say?" I replied: "They have already advised you." He said: "Speak." I said: "Do you make your certainty into conjecture?" He said: "You shall surely have to justify what you have said." I said: "Yes, by Allah, I shall justify it. Do you remember when the Prophet of Allah, peace and blessings of Allah be upon him, sent you as a tax collector, and you went to al-‘Abbas ibn ‘Abd al-Muttalib, and he withheld his charity from you, so there was a dispute between you two?" "You said to me: 'Come with me to the Prophet of Allah, peace and blessings of Allah be upon him.' We found him in a sullen mood, so we returned. Then we went to him the next morning and found him in good spirits. I informed him of what had happened, and he said to you: 'Do you not know that a man’s paternal uncle is like his father?'" "We mentioned to him what we had seen of his sullenness on the first day, and what we had seen of his good spirits on the second day. He said: 'You came to me on the first day while there were two dinars of the charity remaining with me, and that which you saw of my sullenness was due to them. You came to me today, and I have already distributed them, and that is what you saw of my good spirits.'" ‘Umar said: "You have spoken the truth. By Allah, I shall surely thank you for the first and the last."