Volume 5, Book 58, Number 205:
Narrated ‘Abdullah bin ‘Umar:
When ‘Umar embraced Islam, all The (disbelieving) people gathered around his home and said,
“‘Umar has embraced Islam.” At that time I was still a boy and was on the roof of my house. There
came a man wearing a cloak of Dibaj (i.e. a kind of silk), and said, “Umar has embraced Islam.
Nobody can harm him for I am his protector.” I then saw the people going away from ‘Umar and
asked who the man was, and they said, “Al-‘As bin Wail.”