Sahih Ibn Khuzaymah

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that while the Messenger of Allah (peace and blessings be upon him) was sitting among the people (outside his house), a man came walking to him and said, "O Messenger of Allah, what is faith (iman)?" The Prophet (peace and blessings be upon him) replied: "Faith is that you believe in Allah, His angels, His books, His meeting, and His messengers, and that you have certainty in the resurrection on the Last Day." He asked, "O Messenger of Allah, what is Islam?" The Prophet (peace and blessings be upon him) replied: "Islam is that you worship Allah and do not associate anything with Him, and you establish prayer, pay the obligatory zakat, and fast in the month of Ramadan." He asked, "O Messenger of Allah, what is the reality of ihsan (excellence)?" The Prophet (peace and blessings be upon him) replied: "Ihsan is that you worship Allah as if you are seeing Him, for if you do not see Him, surely He sees you." He asked, "O Messenger of Allah, when will the Hour (Day of Judgment) come?" The Prophet (peace and blessings be upon him) replied: "The one being asked about it knows no more than the questioner. But I will tell you its signs. When a slave woman gives birth to her master, that will be a sign of the Hour. When the shepherds of sheep boast in constructing tall buildings, that will be a sign of the Hour. And when the naked, barefoot (poor) people become the leaders of the people, that will be a sign of the Hour. The knowledge of the Hour is among the five things which none knows except Allah." Then he recited the verse « إِنَّ اللَّهَ عِندَهُ عِلْمُ السَّاعَةِ وَيُنَزِّلُ الْغَيْثَ وَيَعْلَمُ مَا فِي الْأَرْحَامِ ۖ وَمَا تَدْرِي نَفْسٌ مَّاذَا تَكْسِبُ غَدًا ۖ وَمَا تَدْرِي نَفْسٌ بِأَيِّ أَرْضٍ تَمُوتُ ۚ إِنَّ اللَّهَ عَلِيمٌ خَبِيرٌ » [ سورة لقمان : 34 ] "Indeed, the knowledge of the Hour is with Allah alone, and He sends down the rain, and He knows what is in the wombs. And no soul knows what it will earn tomorrow, and no soul knows in which land it will die. Indeed, Allah is All-Knowing, All-Aware." Then that man turned his back and left, so the Noble Prophet (peace and blessings be upon him) said: "This was Jibreel (Gabriel), he came to teach the people their religion." This narration is from Muhammad bin Bishr.