It is narrated from Sayyiduna Umar bin Khattab (may Allah be pleased with him), he says: One day we were sitting with the Prophet of Allah (peace and blessings be upon him), when suddenly a man came to us. His clothes were extremely white and his hair was very black. There were no signs of travel visible on him, nor did any of us recognize him. Anyway, he came and sat near the Noble Prophet (peace and blessings be upon him) in such a way that he joined his knees with the knees of the Prophet (peace and blessings be upon him) and placed his hands on the thighs of the Prophet (peace and blessings be upon him) and said: "O Muhammad! Tell me about Islam, what is Islam?" The Prophet (peace and blessings be upon him) said: "Islam is that you bear witness that Allah alone is the true deity and Muhammad (peace and blessings be upon him) is the Messenger of Allah, and that you establish prayer, pay zakat, fast in Ramadan, and if you have the ability, perform Hajj to the House of Allah." He replied: "You have spoken the truth." We were greatly astonished that this person asks questions and also confirms the answers. Anyway, he then asked another question and said: "Tell me about Iman (faith)." The Prophet (peace and blessings be upon him) said: "Iman is that you believe in Allah, His angels, His books, His messengers, the Last Day, and in all destiny, its good and its bad." He said: "Yes, you have spoken the truth." He asked a third question: "Now tell me about Ihsan, what is Ihsan?" The Prophet (peace and blessings be upon him) said: "Ihsan is that you worship Allah as if you see Him, and if you do not see Him, then (know that) He surely sees you." He then asked: "Tell me about the Hour (Day of Judgment)." The Prophet (peace and blessings be upon him) said: "The one being questioned knows no more about it than the questioner." He said: "Then tell me about its signs." The Prophet (peace and blessings be upon him) said: "They are: the slave woman will give birth to her mistress, and you will see barefoot, naked, destitute shepherds competing in constructing tall buildings." Sayyiduna Umar (may Allah be pleased with him) says: Then that man left, and the Prophet (peace and blessings be upon him) remained silent about him for some time, according to one narration, for three days, and then said to me: "Umar! Do you know who the questioner was?" I said: "Allah and His Messenger know best." The Prophet (peace and blessings be upon him) said: "That was Jibreel (Gabriel), he came to teach you your religion."