Sahih al-Bukhari 120

Arabic

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي أَخِي، عَنِ ابْنِ أَبِي ذِئْبٍ، عَنْ سَعِيدٍ الْمَقْبُرِيِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ حَفِظْتُ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم وِعَاءَيْنِ، فَأَمَّا أَحَدُهُمَا فَبَثَثْتُهُ، وَأَمَّا الآخَرُ فَلَوْ بَثَثْتُهُ قُطِعَ هَذَا الْبُلْعُومُ‏.‏

English translation

Narrated Abu Huraira:I have memorized two kinds of knowledge from Allah's Messenger (ﷺ) . I have propagated one of them to you and if I propagated the second, then my pharynx (throat) would be cut (i.e. killed)

Reference: Sahih al-Bukhari 120, Book of Knowledge. English translation by Dr. Muhammad Muhsin Khan.