Sahih Bukhari Volume 2, Book 23, Hadith Number 364.

Narated By Sad from his father : Once the meal of ‘Abdur-Rahman bin ‘Auf was brought in front of him, and he said, “Mustab bin ‘Umar was martyred and he was better than I, and he had nothing except his Burd (a black square narrow dress) to be shrouded in. Hamza or another person was martyred and he was also better than I and he had nothing to be shrouded in except his Burd. No doubt, I fear that the rewards of my deeds might have been given early in this world.” Then he started weeping.