Abu Abd al-Rahman (may Allah have mercy on him) said: When Sayyiduna Uthman (may Allah be pleased with him) was besieged, Sayyiduna Uthman (may Allah be pleased with him) looked down upon them from the roof and said: "I adjure you by Allah - and I adjure only the Companions of the Prophet (peace and blessings be upon him) - you know that the Messenger of Allah (peace and blessings be upon him) said: 'Whoever digs the well of Rumah (Bi'r Rumah), Paradise is for him,' and I dug it. Do you not know that he said: 'Whoever equips the Army of Hardship (Jaysh al-'Usrah - the army of the Battle of Tabuk), Paradise is for him,' and I equipped it?" They affirmed what he said.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوقف / 11933