Sahih Bukhari
Merits of the Helpers in Madinah (Ansaar)
Volume: 005 / Book Number: 058 / Hadith Number: 198
Narrated Abu Ishaq Saud bin Abi Waqqas:
None embraced Islam, except on the day I embraced it. And for seven days I was one of the three persons who were Muslims (one-third of Islam).