Abdullah bin Safwan (may Allah have mercy on him): while he was burying his father, a rider came to him and said: The Commander of the Believers, Uthman bin Affan (may Allah be pleased with him), has been killed. He said: "By Allah, I do not know which of the two calamities is greater: the death of my father or the killing of Uthman?"
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7292