Saad bin Abu Waqqas reported,

No one had embraced Islam except on the day I embraced it. I remained for seven days as one of only three Muslims.

Azami 9957

Sahih

عن سعد بن أبي وقاص يقول

ما أسلم أحد إلا في اليوم الذي أسلمت فيه، ولقد مكثت سبعة أيام وإني لثلث الإسلام.

الأعظمي 9957صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Virtues of the Companions and reports about them
Chapter
Virtues and reports of Saad bin Abu Waqqas
Section
Saad accepted Islam on the day he accepted Islam when he was one third of Islam
Numbering
Jami al-Kamil 9957 (2nd edition)
Azami 9957