كتاب الإيمان
1
The Book of Faith
(78)
Chapter: The saying of the Prophet (saws): "Light, How could I see Him?" and: "I saw Light"
(78)
باب فِي قَوْلِهِ عَلَيْهِ السَّلاَمُ ‏"‏ نُورٌ أَنَّى أَرَاهُ ‏"‏ ‏.‏ وَفِي قَوْلِهِ ‏"‏ رَأَيْتُ نُورًا

Abdullah b. Shaqiq reported:

I said to Abu Dharr: Had I seen the Messenger of Allah, I would have asked him. He (Abu Dharr) said: What is that thing that you wanted to inquire of him? He said: I wanted to ask him whether he had seen his Lord. Abu Dharr said: I, in fact, inquired of him, and he replied: I saw Light.
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا مُعَاذُ بْنُ هِشَامٍ، حَدَّثَنَا أَبِي ح، وَحَدَّثَنِي حَجَّاجُ بْنُ الشَّاعِرِ، حَدَّثَنَا عَفَّانُ بْنُ مُسْلِمٍ، حَدَّثَنَا هَمَّامٌ، كِلاَهُمَا عَنْ قَتَادَةَ، عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ، قَالَ قُلْتُ لأَبِي ذَرٍّ لَوْ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم لَسَأَلْتُهُ فَقَالَ عَنْ أَىِّ شَىْءٍ كُنْتَ تَسْأَلُهُ قَالَ كُنْتُ أَسْأَلُهُ هَلْ رَأَيْتَ رَبَّكَ قَالَ أَبُو ذَرٍّ قَدْ سَأَلْتُ فَقَالَ ‏ "‏ رَأَيْتُ نُورًا ‏"‏ ‏.‏
Reference : Sahih Muslim 178 b
In-book reference : Book 1, Hadith 351
USC-MSA web (English) reference : Book 1, Hadith 342
  (deprecated numbering scheme)