Sahih Bukhari Volume 9, Book 87, Hadith Number 131.

Narrated By Kharija bin Zaid bin Thabit : Um Al-‘Ala an Ansari woman who had given a pledge of allegiance to Allah’s Apostle told me:, “The Muhajirln (emigrants) were distributed amongst us by drawing lots, and we got ‘Uthman bin Maz’un in our share. We made him stay with us in our house. Then he suffered from a disease which proved fatal. When he died and was given a bath and was shrouded in his clothes. Allah’s Apostle came, I said, (addressing the dead body), ‘O Aba As-Sa’ib! May Allah be Merciful to you! I testify that Allah has honored you.’ Allah’s Apostle said, ‘How do you know that Allah has honored him?” I replied, ‘Let my father be sacrificed for you, O Allah’s Apostle! On whom else shall Allah bestow. His honor?’ Allah’s Apostle said, ‘As for him, by Allah, death has come to him. By Allah, I wish him all good (from Allah). By Allah, in spite of the fact that I am Allah’s Apostle, I do not know what Allah will do to me.”, Um Al-‘Ala added, “By Allah, I will never attest the righteousness of anybody after that.”