Abu al-Nadr says that during the time of Hajjaj bin Yusuf, an elder from Banu Tamim came and sat next to me in a mosque in Basra. He also had a scroll in his hand. He said to me, "O servant of Allah! What do you think, can this letter benefit me in front of this king?" I asked, "What kind of letter is this?" He replied, "This is the statement of the Prophet (peace be upon him) which he had written for us, that there should be no excess in the collection of zakat from us." I said, "By Allah! I do not think this letter will benefit you (because Hajjaj is very oppressive), but tell me, what is the matter of this letter?" He said, "Once I came to Madinah with my father; at that time I was a young man. We wanted to sell one of our camels. My father was a friend of Sayyiduna Talhah bin Ubaidullah (may Allah be pleased with him), so we went and stayed with him. My father said to him, 'Come with me and help me sell this camel.' He said, 'The Messenger of Allah (peace be upon him) has forbidden that a townsman should buy or sell on behalf of a villager. However, I will go with you and sit with you. You present your camel before the people. Whomever I am satisfied with, that he will pay the price and prove to be truthful, I will tell you to sell it to him.' So we went out and reached the market and stopped at a place. Sayyiduna Talhah (may Allah be pleased with him) sat nearby. Many people came and bargained, until a man came who was ready to pay our asking price. My father asked him, 'Shall I deal with him?' He replied in the affirmative and said, 'I am satisfied that he will pay your price in full, so sell this camel to him.' So we sold the camel to him. When we received the money and our need was fulfilled, my father said to Sayyiduna Talhah (may Allah be pleased with him), 'Please have a letter written by the Prophet (peace be upon him) for us, stating that there should be no excess in the collection of zakat from us.' He replied, 'This is for you and for every Muslim.' The narrator says, 'That is why I wanted to have a letter from the Prophet (peace be upon him) with me.' Anyway, Sayyiduna Talhah (may Allah be pleased with him) went with us to the service of the Prophet (peace be upon him) and said, 'O Messenger of Allah! This person, who is from a village, is our friend. He wishes that you have a letter written for him of this nature, that there should be no excess in the collection of zakat from him.' He said, 'This is for him and for every Muslim.' My father said, 'O Messenger of Allah! I wish to have a letter from you on this subject with me.' So the Prophet (peace be upon him) had this letter written for us."

The last hadith of Talha ibn Ubaydullah, may Allah be pleased with him.