Ahnaf bin Qays (may Allah have mercy on him) narrated a story in which Sayyiduna Uthman (may Allah be pleased with him) came and asked: "Is Ali (may Allah be pleased with him) here?" They said: "Yes." Then he asked about Talhah (may Allah be pleased with him), and they said: "Yes." Then he asked: "Is al-Zubayr (may Allah be pleased with him) here?" They said: "Yes." Then he asked: "Is Sa'd (may Allah be pleased with him) here?" They said: "Yes." Then he said: "I adjure you by Allah, besides whom there is no god: do you know that the Messenger of Allah (peace and blessings be upon him) said: 'Whoever buys the date-drying yard of Banu so-and-so, Allah will forgive him,' so I bought it - the narrator said: I think he said: for twenty or twenty-five thousand - then I came to the Messenger of Allah (peace and blessings be upon him) and said: 'I have bought it,' and he said: 'Add it to our mosque, and its reward is yours'?" They said: "Yes." He said: "I adjure you by Allah, besides whom there is no god: do you know that the Messenger of Allah (peace and blessings be upon him) said: 'Whoever buys the well of Rumah, Allah will forgive him,' so I bought it. Then I came to the Messenger of Allah (peace and blessings be upon him) and said: 'I have bought the well of Rumah,' and he said: 'Make it a source of drinking water for the Muslims, and its reward is yours'?" They answered yes. Then he said: "I adjure you by Allah, besides whom there is no god: you know that the Messenger of Allah (peace and blessings be upon him) looked at the faces of the army of the Battle of Tabuk and said: 'Whoever equips this army, Allah will forgive him.' So I equipped them until they did not lack even a halter or a hobbling rope?" They answered yes. Then Sayyiduna Uthman (may Allah be pleased with him) said: "O Allah, be witness!" He said these words three times.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوقف / 11935