كتاب صلاة المسافرين وقصرها
6
The Book of Prayer - Travellers
(43)
Chapter: The virtue of al-Fatihah and the closing verse of Surat al-Baqarah; and the encouragement to recite the two verses at the end of Surat al-Baqarah
(43)
اب فَضْلِ الْفَاتِحَةِ وَخَوَاتِيمِ سُورَةِ الْبَقَرَةِ وَالْحَثِّ عَلَى قِرَاءَةِ الآيَتَيْنِ مِنْ آخِرِ الْبَقَرَةِ
Sahih Muslim 806

Ibn 'Abbas reported that while Gabriel was sitting with the Apostle (ﷺ) he heard a creaking sound above him. He lifted his head and said:

This is a gate opened in heaven today which had never been opened before. Then when an angel descended through it, he said: This is an angel who came down to the earth who had never come down before. He greeted and said: Rejoice in two lights given to you which have not been given to any prophet before you: Fatihat al-Kitab and the concluding verses of Surah al-Baqara. You will never recite a letter from them for which you will not be given (a reward).
حَدَّثَنَا حَسَنُ بْنُ الرَّبِيعِ، وَأَحْمَدُ بْنُ جَوَّاسٍ الْحَنَفِيُّ، قَالاَ حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ عَمَّارِ بْنِ رُزَيْقٍ، عَنْ عَبْدِ اللَّهِ بْنِ عِيسَى، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ بَيْنَمَا جِبْرِيلُ قَاعِدٌ عِنْدَ النَّبِيِّ صلى الله عليه وسلم سَمِعَ نَقِيضًا مِنْ فَوْقِهِ فَرَفَعَ رَأْسَهُ فَقَالَ هَذَا بَابٌ مِنَ السَّمَاءِ فُتِحَ الْيَوْمَ لَمْ يُفْتَحْ قَطُّ إِلاَّ الْيَوْمَ فَنَزَلَ مِنْهُ مَلَكٌ فَقَالَ هَذَا مَلَكٌ نَزَلَ إِلَى الأَرْضِ لَمْ يَنْزِلْ قَطُّ إِلاَّ الْيَوْمَ فَسَلَّمَ وَقَالَ أَبْشِرْ بِنُورَيْنِ أُوتِيتَهُمَا لَمْ يُؤْتَهُمَا نَبِيٌّ قَبْلَكَ فَاتِحَةُ الْكِتَابِ وَخَوَاتِيمُ سُورَةِ الْبَقَرَةِ لَنْ تَقْرَأَ بِحَرْفٍ مِنْهُمَا إِلاَّ أُعْطِيتَهُ ‏.‏
Reference : Sahih Muslim 806
In-book reference : Book 6, Hadith 305
USC-MSA web (English) reference : Book 4, Hadith 1760
  (deprecated numbering scheme)