Sunan Ibn Majah 63
It was narrated that 'Umar said:
"We were sitting with the Prophet (ﷺ) when a man came to him whose clothes were intensely white and whose hair was intensely black; no signs of travel could be seen upon him, and none of us recognized him. He sat down facing the Prophet (ﷺ), with his knees touching his, and he put his hands on his thighs, and said: 'O Muhammad, what is Islam?' He said: 'To testify that none has the right to be worshipped but Allah, and that I am the Messenger of Allah, to establish regular prayer, to pay Zakat, to fast in Ramadan, and to perform Hajj to the House (the Ka'bah).' He said: 'You have spoken the truth.' We were amazed by him: He asked a question, then told him that he had spoken the truth. Then he said: 'O Muhammad, what is Iman faith? He said: 'To believe in Allah, His angels, His Messengers, His books, the Last day, and the Divine Decree (Qadar), both the good of it and the bad of it.' He said' You have spoken the truth.' We were amazed by him. He asked a question, then told him that he had spoken the truth. Then he said: 'O Muhammad, what is Ihsan (right action, goodness, sincerity)? He said: 'To worship Allah as if you see Him, for even though you do not see Him, He sees you.' He asked: "When will the Hour be?' He said: 'The one who is being asked about it does not know more than the one who is asking.' He asked: 'Then what are its signs?' he said: 'When the slave woman gives birth to her mistress' (Waki' said: This means when non-Arabs will give birth to Arabs")  'and when you see barefoot, naked, destitute shepherds competing in constructing tall buildings.' The Prophet (ﷺ) met me three days later and asked me: 'Do you know who that man was? I said" 'Allah and his Messenger know best.' He said: 'That was Jibril, who came to you to teach you your religion.'"
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، عَنْ كَهْمَسِ بْنِ الْحَسَنِ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ يَحْيَى بْنِ يَعْمَرَ، عَنِ ابْنِ عُمَرَ، عَنْ عُمَرَ، قَالَ كُنَّا جُلُوسًا عِنْدَ النَّبِيِّ ـ صلى الله عليه وسلم ـ فَجَاءَ رَجُلٌ شَدِيدُ بَيَاضِ الثِّيَابِ شَدِيدُ سَوَادِ شَعَرِ الرَّأْسِ لاَ يُرَى عَلَيْهِ أَثَرُ السَّفَرِ وَلاَ يَعْرِفُهُ مِنَّا أَحَدٌ ‏.‏ قَالَ فَجَلَسَ إِلَى النَّبِيِّ ـ صلى الله عليه وسلم ـ فَأَسْنَدَ رُكْبَتَهُ إِلَى رُكْبَتِهِ وَوَضَعَ يَدَيْهِ عَلَى فَخِذَيْهِ ‏.‏ ثُمَّ قَالَ يَا مُحَمَّدُ مَا الإِسْلاَمُ قَالَ ‏"‏ شَهَادَةُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنِّي رَسُولُ اللَّهِ وَإِقَامُ الصَّلاَةِ وَإِيتَاءُ الزَّكَاةِ وَصَوْمُ رَمَضَانَ وَحَجُّ الْبَيْتِ ‏"‏ ‏.‏ قَالَ صَدَقْتَ ‏.‏ فَعَجِبْنَا مِنْهُ يَسْأَلُهُ وَيُصَدِّقُهُ ‏.‏ ثُمَّ قَالَ يَا مُحَمَّدُ مَا الإِيمَانُ قَالَ ‏"‏ أَنْ تُؤْمِنَ بِاللَّهِ وَمَلاَئِكَتِهِ وَرُسُلِهِ وَكُتُبِهِ وَالْيَوْمِ الآخِرِ وَالْقَدَرِ خَيْرِهِ وَشَرِّهِ ‏"‏ ‏.‏ قَالَ صَدَقْتَ ‏.‏ فَعَجِبْنَا مِنْهُ يَسْأَلُهُ وَيُصَدِّقُهُ ‏.‏ ثُمَّ قَالَ يَا مُحَمَّدُ مَا الإِحْسَانُ قَالَ ‏"‏ أَنْ تَعْبُدَ اللَّهَ كَأَنَّكَ تَرَاهُ فَإِنَّكَ إِنْ لاَ تَرَاهُ فَإِنَّهُ يَرَاكَ ‏"‏ ‏.‏ قَالَ فَمَتَى السَّاعَةُ قَالَ ‏"‏ مَا الْمَسْئُولُ عَنْهَا بِأَعْلَمَ مِنَ السَّائِلِ ‏"‏ ‏.‏ قَالَ فَمَا أَمَارَتُهَا قَالَ ‏"‏ أَنْ تَلِدَ الأَمَةُ رَبَّتَهَا ‏"‏ ‏.‏ قَالَ وَكِيعٌ يَعْنِي تَلِدُ الْعَجَمُ الْعَرَبَ ‏"‏ وَأَنْ تَرَى الْحُفَاةَ الْعُرَاةَ الْعَالَةَ رِعَاءَ الشَّاءِ يَتَطَاوَلُونَ فِي الْبِنَاءِ ‏"‏ ‏.‏ قَالَ ثُمَّ قَالَ فَلَقِيَنِي النَّبِيُّ ـ صلى الله عليه وسلم ـ بَعْدَ ثَلاَثٍ فَقَالَ ‏"‏ أَتَدْرِي مَنِ الرَّجُلُ ‏"‏ ‏.‏ قُلْتُ اللَّهُ وَرَسُولُهُ أَعْلَمُ ‏.‏ قَالَ ‏"‏ ذَاكَ جِبْرِيلُ أَتَاكُمْ يُعَلِّمُكُمْ مَعَالِمَ دِينِكُمْ ‏"‏ ‏.‏