The Hadeeth of Jibreel, ‘alayhis salaam:
‘Umar ibn Al-Khattab, radiAllaahu ‘anh, reported:
“While we were sitting with the Messenger of Allaah, salla Allaahu ‘alayhi wa sallam, a man came up to us whose clothes were extremely white, whose hair was extremely black, upon whom traces of traveling could not be seen, and whom none of us knew, until he sat down close to the Prophet, salla Allaahu ‘alayhi wa sallam, so that he rested his knees upon his knees and placed his two hands upon his thighs and said,
‘Yaa Muhammad, tell me about Islaam.’
The Messenger of Allaah, salla Allaahu ‘alayhi wa sallam, said,
‘Islam is that you witness that there is no god but Allaah and that Muhammad is the Messenger of Allaah, and you establish the prayer, and you give the Zakaat, and you fast Ramadhaan, and you perform the Hajj of the House if you are able to take a way to it.’
He said, ‘You have told the truth,’ and we were amazed at him asking him and [then] telling him that he told the truth.
He said, ‘Tell me about eemaan.’
He salla Allaahu ‘alayhi wa sallam said, ‘That you affirm Allaah, His angels, His books, His messengers, and the Last Day, and that you affirm the Decree, the good of it and the bad of it.’
He said, ‘You have told the truth.’
He said, ‘Tell me about Ihsaan.’
He salla Allaahu ‘alayhi wa sallam said, ‘That you worship Allaah as if you see Him, for if you don’t see Him then truly He sees you.’
He said, ‘Tell me about the Hour.’
He salla Allaahu ‘alayhi wa sallam said, ‘The one asked about it knows no more than the one asking.’
He said, ‘Then tell me about its tokens.’
He salla Allaahu ‘alayhi wa sallam said, ‘That the female slave should give birth to her mistress, and you see poor, naked, barefoot shepherds of sheep and goats competing in making tall buildings.’
He went away, and I remained some time. Then he salla Allaahu ‘alayhi wa sallam asked, ‘ ‘Umar, do you know who the questioner was?’
I said, ‘Allaah and His Messenger know best.’
He salla Allaahu ‘alayhi wa sallam said, ‘He was Jibreel who came to you to teach you your deen’.”
[Narrated by Bukhaari and Muslim]
Miftaahul-Ilm - Key to Knowledge 