Kharijah bin Zayd narrates from Umm al-Ala (may Allah be pleased with her), who had given the pledge of allegiance to the Messenger of Allah (peace and blessings be upon him). She reports that when lots were drawn between the Ansar and the Muhajirun (for lodging), the lot for the lodging of Uthman bin Maz'un (may Allah be pleased with him) fell to them. Umm al-Ala (may Allah be pleased with her) said: Uthman bin Maz'un (may Allah be pleased with him) stayed with us and fell ill. We nursed him until he passed away, and we wrapped him in his clothes. The Messenger of Allah (peace and blessings be upon him) came to us, and I said: "May the mercy of Allah be upon you, O Abu al-Sa'ib! I bear witness for you that Allah has honoured you." The Prophet (peace and blessings be upon him) said: "How do you know that Allah has honoured him?" I said: I do not know, O Messenger of Allah (peace and blessings be upon him), may my father and mother be sacrificed for you. The Prophet (peace and blessings be upon him) said: "As for Uthman, al-yaqin (death) has come to him, and I hope for good for him from Allah. By Allah, I am the Messenger of Allah, yet I do not know what will be done with me." She said: By Allah, after that I never declared anyone (definitively) pure, and that saddened me. Then I slept, and in a dream I was shown a flowing spring belonging to Uthman (may Allah be pleased with him). I came to the Messenger of Allah (peace and blessings be upon him) and told him of it, and he (peace and blessings be upon him) said: "That is (the reward of) his deeds."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7190
Kharijah bin Zayd (may Allah have mercy on him) said that Umm al-Ala al-Ansariyyah (may Allah be pleased with her) used to say, and he mentioned the meaning of this hadith, except that he said: "what will be done with him." He added: Ma'mar said: I heard someone other than al-Zuhri say: The Muslims were troubled by what the Messenger of Allah (peace and blessings be upon him) said about Uthman, until the daughter of the Prophet (peace and blessings be upon him) passed away, and he (peace and blessings be upon him) said: "Join our forerunner, Uthman bin Maz'un."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7191