Sahih al-Bukhari, Book 65, Hadith 4621 (In-Book) ⓘ

Narrated Anas: The Prophet delivered a sermon the like of which I had never heard before. He said, "If you but knew what I know then you would have laughed little and wept much." On hearing that, the companions of the Prophet covered their faces and the sound of their weeping was heard. A man said, "Who is my father?" The Prophet said, "So-and-so." So this Verse was revealed: "Ask not about things which, if made plain to you, may cause you trouble." (5.101)

حَدَّثَنَا مُنْذِرُ بْنُ الْوَلِيدِ بْنِ عَبْدِ الرَّحْمَنِ الْجَارُودِيُّ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، عَنْ مُوسَى بْنِ أَنَسٍ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ خَطَبَ رَسُولُ اللَّهِ صلى الله عليه وسلم خُطْبَةً مَا سَمِعْتُ مِثْلَهَا قَطُّ، قَالَ ‏"‏ لَوْ تَعْلَمُونَ مَا أَعْلَمُ لَضَحِكْتُمْ قَلِيلاً وَلَبَكَيْتُمْ كَثِيرًا ‏"‏‏.‏ قَالَ فَغَطَّى أَصْحَابُ رَسُولِ اللَّهِ صلى الله عليه وسلم وُجُوهَهُمْ لَهُمْ خَنِينٌ، فَقَالَ رَجُلٌ مَنْ أَبِي قَالَ فُلاَنٌ فَنَزَلَتْ هَذِهِ الآيَةُ ‏{‏لاَ تَسْأَلُوا عَنْ أَشْيَاءَ إِنْ تُبْدَ لَكُمْ تَسُؤْكُمْ‏}‏‏.‏ رَوَاهُ النَّضْرُ وَرَوْحُ بْنُ عُبَادَةَ عَنْ شُعْبَةَ‏.‏