What is Iman (Faith) and what are its characteristics

2 Abu Hurairah, may Allah be pleased with him, reported: One day Allah's Messenger (may peace be upon him) appeared before the public. Then a man came to him and asked: Prophet of Allah, what is Iman? Upon this he (the Holy Prophet) replied: That you affirm your faith in Allah, His angels, His Books, His meeting, His Messengers and that you affirm your faith in the Resurrection hereafter. He (again) asked: Messenger of Allah, what does Islam signify? He (the Holy Prophet) replied: Islam signifies that you worship Allah and do not associate anything with Him and you perform the prescribed Prayer and you pay the obligatory poor-due (Zakah) and you observe the Fast of Ramadan. He (the inquirer) again asked: Messenger of Allah, what does Al-Ihsan (Faithfulness) imply? He (the Holy Prophet) replied: That you worship Allah as if you are seeing Him, and in case you fail to see Him, then observe that He is seeing you. He (the inquirer) again asked: Messenger of Allah, when would there be the Hour of (Doom)? He (the Holy Prophet) replied: The one who is asked about it is no better informed than the inquirer. I, however, will narrate some of its signs (and these are): When the female-slave will give birth to her master, when the naked, barefooted would become the chiefs of the people; these are some of the signs of (Doom). (Moreover) when the shepherds of the black (camels) would exalt themselves in buildings, this is one of the signs of (Doom). (Doom) is one of the five (happenings wrapped in the unseen) which no one but Allah knows. Then he (the Messenger of Allah) (may peace be upon him) recited (the verse): Verily Allah! with Him alone is the knowledge of the Hour and it is Him Who sends down the rain and knows that which is in the wombs and no person knows whatsoever he shall earn tomorrow, and a person knows not in whatsoever land he shall die. Verily Allah is Knowing, Aware He (the narrator, Abu Hurairah) said: Then the person turned back and went away. Allah's Messenger (may peace be upon him) said: Bring that man back to me. They (the Companions of the Holy Prophet present there) went to bring him back, but they did not find him. Upon this Allah's Messenger (may peace be upon him) remarked: He was Gabriel. He came to teach people their religion.