Narrated Abu Huraira:

One day while the Prophet (ﷺ) was sitting in the company of some people, (The angel) Gabriel came and asked, "What is faith?" Allah's Messenger (ﷺ) replied, 'Faith is to believe in Allah, His angels, (the) meeting with Him, His Apostles, and to believe in Resurrection." Then he further asked, "What is Islam?" Allah's Messenger (ﷺ) replied, "To worship Allah Alone and none else, to offer prayers perfectly to pay the compulsory charity (Zakat) and to observe fasts during the month of Ramadan." Then he further asked, "What is Ihsan (perfection)?" Allah's Messenger (ﷺ) replied, "To worship Allah as if you see Him, and if you cannot achieve this state of devotion then you must consider that He is looking at you." Then he further asked, "When will the Hour be established?" Allah's Messenger (ﷺ) replied, "The answerer has no better knowledge than the questioner. But I will inform you about its portents.

1. When a slave (lady) gives birth to her master.

2. When the shepherds of black camels start boasting and competing with others in the construction of higher buildings. And the Hour is one of five things which nobody knows except Allah.

The Prophet (ﷺ) then recited: "Verily, with Allah (Alone) is the knowledge of the Hour--." (31. 34) Then that man (Gabriel) left and the Prophet (ﷺ) asked his companions to call him back, but they could not see him. Then the Prophet (ﷺ) said, "That was Gabriel who came to teach the people their religion." Abu 'Abdullah said: He (the Prophet) considered all that as a part of faith.

Narrated Abu Huraira:

One day while Allah's Messenger (ﷺ) was sitting with the people, a man came to him walking and said, "O Allah's Messenger. What is Belief?" The Prophet (ﷺ) said, "Belief is to believe in Allah, His Angels, His Books, His Apostles, and the meeting with Him, and to believe in the Resurrection." The man asked, "O Allah's Messenger (ﷺ) What is Islam?" The Prophet (ﷺ) replied, "Islam is to worship Allah and not worship anything besides Him, to offer prayers perfectly, to pay the (compulsory) charity i.e. Zakat and to fast the month of Ramadan." The man again asked, "O Allah's Messenger (ﷺ) What is Ihsan (i.e. perfection or Benevolence)?" The Prophet (ﷺ) said, "Ihsan is to worship Allah as if you see Him, and if you do not achieve this state of devotion, then (take it for granted that) Allah sees you." The man further asked, "O Allah's Messenger (ﷺ) When will the Hour be established?" The Prophet (ﷺ) replied, "The one who is asked about it does not know more than the questioner does, but I will describe to you its portents. When the lady slave gives birth to her mistress, that will be of its portents; when the bare-footed naked people become the chiefs of the people, that will be of its portents. The Hour is one of five things which nobody knows except Allah. Verily, the knowledge of the Hour is with Allah (alone). He sends down the rain, and knows that which is in the wombs." (31.34) Then the man left. The Prophet (ﷺ) said, "Call him back to me." They went to call him back but could not see him. The Prophet (ﷺ) said, "That was Gabriel who came to teach the people their religion." (See Hadith No. 47 Vol 1)

Narrated `Abdullah bin `Umar:

The Prophet (ﷺ) said, "The keys of the Unseen are five." And then he recited: 'Verily, the knowledge of the Hour is with Allah (alone).' (31.34)

Narrated Masruq:

I said to `Aisha, "O Mother! Did Prophet Muhammad see his Lord?" Aisha said, "What you have said makes my hair stand on end ! Know that if somebody tells you one of the following three things, he is a liar: Whoever tells you that Muhammad saw his Lord, is a liar." Then Aisha recited the Verse: 'No vision can grasp Him, but His grasp is over all vision. He is the Most Courteous Well-Acquainted with all things.' (6.103) 'It is not fitting for a human being that Allah should speak to him except by inspiration or from behind a veil.' (42.51) `Aisha further said, "And whoever tells you that the Prophet knows what is going to happen tomorrow, is a liar." She then recited: 'No soul can know what it will earn tomorrow.' (31.34) She added: "And whoever tell you that he concealed (some of Allah's orders), is a liar." Then she recited: 'O Apostle! Proclaim (the Message) which has been sent down to you from your Lord..' (5.67) `Aisha added. "But the Prophet (ﷺ) saw Gabriel in his true form twice."