Abu Abd al-Rahman al-Sulami (may Allah have mercy on him) said: When Sayyiduna Uthman bin Affan (may Allah be pleased with him) was besieged and his house was surrounded, he looked out over the people and said: "I adjure you by Allah, do you know that the Messenger of Allah (peace and blessings be upon him) was on the mountain of Hira and said: 'Be still, Hira! For upon you there is none but a Prophet, a Siddiq, or a martyr'?" They answered yes.
Then he said: "I adjure you by Allah, (do you know) that the Messenger of Allah (peace and blessings be upon him) said during the Battle of Tabuk: 'Who will spend an expenditure that will be accepted?' - and the people on that day were in hardship - and I bore the expense of one third of that army from my own wealth?" They answered yes. Then he said: "I adjure you by Allah, (do you know that) at a time when water was bought to be drunk, I bought the well of Rumah and endowed it for everyone - for the rich, the poor and the wayfarer?" They answered yes, and he enumerated a number of things.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوقف / 11934