Sahih Bukhari Volume 6, Book 66, Hadith 5014

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، 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 رَسُولُ اللَّهِ صلى الله عليه وسلم ثُمَّ سَأَلَهُ فَلَمْ يُجِبْهُ ثُمَّ سَأَلَهُ فَلَمْ يُجِبْهُ، فَقَالَ عُمَرُ ثَكِلَتْكَ أُمُّكَ نَزَرْتَ رَسُولَ اللَّهِ صلى الله عليه وسلم ثَلاَثَ مَرَّاتٍ كُلَّ ذَلِكَ لاَ يُجِيبُكَ، قَالَ عُمَرُ فَحَرَّكْتُ بَعِيرِي حَتَّى كُنْتُ أَمَامَ النَّاسِ وَخَشِيتُ أَنْ يَنْزِلَ فِيَّ قُرْآنٌ فَمَا نَشِبْتُ أَنْ سَمِعْتُ صَارِخًا يَصْرُخُ ـ قَالَ ـ فَقُلْتُ لَقَدْ خَشِيتُ أَنْ يَكُونَ نَزَلَ فِيَّ قُرْآنٌ ـ قَالَ ـ فَجِئْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم فَسَلَّمْتُ عَلَيْهِ فَقَالَ ‏"‏ لَقَدْ أُنْزِلَتْ عَلَىَّ اللَّيْلَةَ سُورَةٌ لَهِيَ أَحَبُّ إِلَىَّ مِمَّا طَلَعَتْ عَلَيْهِ الشَّمْسُ ‏"‏‏.‏ ثُمَّ قَرَأَ ‏{‏إِنَّا فَتَحْنَا لَكَ فَتْحًا مُبِينًا‏}‏

Narrated By Aslam : Allah's Apostle was travelling on one of his journeys, and 'Umar bin Al-Khattab was travelling along with him at night. 'Umar asked him about something, but Allah's Apostle did not answer him. He asked again, but he did not answer. He asked for the third time!, but he did not answer. On that, 'Umar said to himself, "May your mother lose you! You have asked Allah's Apostle three times, but he did not answer at all!" Umar said, "So I made my camel go fast till I was ahead of the people, and I was afraid that something might be! revealed about me. After a little while I heard a call maker calling me, I said, 'I was afraid that some Qur'anic Verse might be revealed about me.' So I went to Allah's Apostle and greeted him. He said, 'Tonight there has been revealed to me a Surah which is dearer to me than that on which the sun shines (i.e. the world).' Then he recited: 'Verily! We have given you (O Muhammad I, a manifest victory.' " (Surat al-Fath) No. (48.1).