Sahih al-Bukhari 4931b
Narrated `Abdullah:
While we were with Allah's Messenger (ﷺ) in a cave, Surat "Wal Mursalat" was revealed to him and we 
received it directly from his mouth as soon as he had received the revelation. Suddenly a snake came 
out and Allah's Messenger (ﷺ) said, "Get at it and kill it!" We ran to kill it but it outstripped us. Allah's 
Apostle said, "It has escaped your evil, as you too, have escaped its."
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، قَالَ قَالَ عَبْدُ اللَّهِ بَيْنَا نَحْنُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي غَارٍ إِذْ نَزَلَتْ عَلَيْهِ وَالْمُرْسَلاَتِ فَتَلَقَّيْنَاهَا مِنْ فِيهِ وَإِنَّ فَاهُ لَرَطْبٌ بِهَا إِذْ خَرَجَتْ حَيَّةٌ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ عَلَيْكُمُ اقْتُلُوهَا ‏"‏‏.‏ قَالَ فَابْتَدَرْنَاهَا فَسَبَقَتْنَا ـ قَالَ ـ فَقَالَ ‏"‏ وُقِيَتْ شَرَّكُمْ، كَمَا وُقِيتُمْ شَرَّهَا ‏"‏‏.‏