Muwatta Malik, Book 15, Hadith 9 (USC-MSA)

Yahya related to me from Malik from Zayd ibn Aslam from his father that the Messenger of Allah, may Allah bless him and grant him peace, was on one of his journeys, and one night Umar ibn al-Khattab, who was travelling with him, asked him about something, but he did not answer him. He asked him again, but he did not answer him. Then he asked him again, and again he did not answer him. Umar said, "May your mother be bereaved of you, Umar. Three times you have importuned the Messenger of Allah, may Allah bless him and grant him peace, with a question and he has not answered you at all." Umar continued, "I got my camel moving until, when I was in front of the people, I feared that a piece of Qur'an was being sent down about me. It was not long before I heard a crier calling for me, and I said that I feared that a piece of Qur'an had been sent down about me." He continued, "I came to the Messenger of Allah, may Allah bless him and grant him peace, and said, 'Peace be upon you' to him, and he said, 'A sura has been sent down to me this night that is more beloved to me than anything on which the sun rises.' Then he recited al-Fath (Sura 48).

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَسِيرُ فِي بَعْضِ أَسْفَارِهِ وَعُمَرُ بْنُ الْخَطَّابِ يَسِيرُ مَعَهُ لَيْلاً فَسَأَلَهُ عُمَرُ عَنْ شَىْءٍ فَلَمْ يُجِبْهُ ثُمَّ سَأَلَهُ فَلَمْ يُجِبْهُ ثُمَّ سَأَلَهُ فَلَمْ يُجِبْهُ ‏.‏ فَقَالَ عُمَرُ ثَكِلَتْكَ أُمُّكَ عُمَرُ نَزَرْتَ رَسُولَ اللَّهِ صلى الله عليه وسلم ثَلاَثَ مَرَّاتٍ كُلُّ ذَلِكَ لاَ يُجِيبُكَ - قَالَ عُمَرُ - فَحَرَّكْتُ بَعِيرِي حَتَّى إِذَا كُنْتُ أَمَامَ النَّاسِ وَخَشِيتُ أَنْ يُنْزَلَ فِيَّ قُرْآنٌ فَمَا نَشِبْتُ أَنْ سَمِعْتُ صَارِخًا يَصْرُخُ بِي - قَالَ - فَقُلْتُ لَقَدْ خَشِيتُ أَنْ يَكُونَ نَزَلَ فِيَّ قُرْآنٌ - قَالَ - فَجِئْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم فَسَلَّمْتُ عَلَيْهِ فَقَالَ ‏"‏ لَقَدْ أُنْزِلَتْ عَلَىَّ هَذِهِ اللَّيْلَةَ سُورَةٌ لَهِيَ أَحَبُّ إِلَىَّ مِمَّا طَلَعَتْ عَلَيْهِ الشَّمْسُ ‏"‏ ‏.‏ ثُمَّ قَرَأَ ‏{‏ إِنَّا فَتَحْنَا لَكَ فَتْحًا مُبِينًا ‏}‏

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also referenced under: Book 15, Hadith 481 (In-Book)