Hadith 2 of Nawawi : « O Muhammad, tell me about Islam. »

On the authority of Umar ibn al-Khattab (may Allah be pleased with him), who said: One day while we were with the Messenger of Allah (peace and blessings of Allah be upon him), a man appeared whose clothes were extremely white and whose hair was extremely black, with no signs of travel upon him, and none of us knew him. He sat before the Prophèt, joining his knees to his and placing his palms on his thighs, and said: « O Muhammad, tell me about Islam. » The Messenger of Allah said: « Islam is to testify that there is no deity but Allah and that Muhammad is the Messenger of Allah, to establish the prayer, to give the zakat, to fast Ramadan, and to make the pilgrimage to the House if you can find a way. » He said: « You have spoken truly. » We were amazed that he asked and then confirmed. He said: « Tell me about iman (faith). » He said: « It is to believe in Allah, His angels, His books, His messengers, the Last Day, and to believe in the decree, its good and its evil. » He said: « You have spoken truly. » He said: « Tell me about ihsan (excellence). » He said: « It is to worship Allah as though you see Him, for though you do not see Him, He sees you. » He said: « Tell me about the Hour. » He said: « The questioned knows no more than the questioner. » He said: « Then tell me about its signs. » He said: « That the slave-girl will give birth to her mistress, and that you see barefoot, naked, destitute shepherds competing in building tall structures. » Then he departed. I stayed a long while. Then he said: « Umar, do you know who the questioner was? » I said: « Allah and His Messenger know best. » He said: « It was Jibril, who came to teach you your religion. » Narrated by Muslim.