It was narrated that Hashim bin Hashim said:
"I heard Sa'eed bin Musayyab say: 'Sa'd bin Abu Waqqas said: 'No one else became Muslim on the same day as I did; for seven days I was one-third of Islam.'" (DE)
English reference (DE): Vol. 1, Book 1, Hadith 132 (DE)
Arabic reference (DE): Book 1, Hadith 137 (DE)