Anas b. Malik reported that something was conveyed to him (the Holy prophet) about his Companions, so he addressed them and said:

Paradise and Hell were presented to me and I have never seen the good and evil as (I did) today. And if you were to know you would have wept more and laughed less. He (the narrator) said: There was nothing more burdensome for the Companions of Allah's Messenger (ﷺ) than this. They covered their heads and the sound of weeping was heard from them. Then there stood up 'Umar and he said: We are well pleased with Allah as our Lord, with Islam as our code of life and with Muhammad as our Messenger, and it was at that time that a person stood up and he said: Who is my father? Thereupon he (the Prophet) said: Your father is so and so; and there was revealed the verse:" O you who believe, do not ask about matters which, if they were to be made manifest to you (in terms of law), might cause to you harm" (v. 101).

حَدَّثَنَا مَحْمُودُ بْنُ غَيْلاَنَ، وَمُحَمَّدُ بْنُ قُدَامَةَ السُّلَمِيُّ، وَيَحْيَى بْنُ مُحَمَّدٍ اللُّؤْلُؤِيُّ، - وَأَلْفَاظُهُمْ مُتَقَارِبَةٌ قَالَ مَحْمُودٌ حَدَّثَنَا النَّضْرُ بْنُ شُمَيْلٍ، وَقَالَ الآخَرَانِ، أَخْبَرَنَا النَّضْرُ، - أَخْبَرَنَا شُعْبَةُ، حَدَّثَنَا مُوسَى بْنُ أَنَسٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ بَلَغَ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ أَصْحَابِهِ شَىْءٌ فَخَطَبَ فَقَالَ ‏"‏ عُرِضَتْ عَلَىَّ الْجَنَّةُ وَالنَّارُ فَلَمْ أَرَ كَالْيَوْمِ فِي الْخَيْرِ وَالشَّرِّ وَلَوْ تَعْلَمُونَ مَا أَعْلَمُ لَضَحِكْتُمْ قَلِيلاً وَلَبَكَيْتُمْ كَثِيرًا ‏"‏ ‏.‏ قَالَ فَمَا أَتَى عَلَى أَصْحَابِ رَسُولِ اللَّهِ صلى الله عليه وسلم يَوْمٌ أَشَدُّ مِنْهُ - قَالَ - غَطَّوْا رُءُوسَهُمْ وَلَهُمْ خَنِينٌ - قَالَ - فَقَامَ عُمَرُ فَقَالَ رَضِينَا بِاللَّهِ رَبًّا وَبِالإِسْلاَمِ دِينًا وَبِمُحَمَّدٍ نَبِيًّا - قَالَ - فَقَامَ ذَاكَ الرَّجُلُ فَقَالَ مَنْ أَبِي قَالَ ‏"‏ أَبُوكَ فُلاَنٌ ‏"‏ ‏.‏ فَنَزَلَتْ ‏{‏ يَا أَيُّهَا الَّذِينَ آمَنُوا لاَ تَسْأَلُوا عَنْ أَشْيَاءَ إِنْ تُبْدَ لَكُمْ تَسُؤْكُمْ‏}‏