Sahih al-Bukhari 1830
Narrated `Abdullah:
While we were in the company of the Prophet (ﷺ) in a cave at Mina, when Surat-wal-Mursalat were 
revealed and he recited it and I heard it (directly) from his mouth as soon as he recited its revelation. 
Suddenly a snake sprang at us and the Prophet (ﷺ) said (ordered us): "Kill it." We ran to kill it but it 
escaped quickly. The Prophet (ﷺ) said, "It has escaped your evil and you too have escaped its evil."
حَدَّثَنَا عُمَرُ بْنُ حَفْصِ بْنِ غِيَاثٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا الأَعْمَشُ، قَالَ حَدَّثَنِي إِبْرَاهِيمُ، عَنِ الأَسْوَدِ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ بَيْنَمَا نَحْنُ مَعَ النَّبِيِّ صلى الله عليه وسلم فِي غَارٍ بِمِنًى، إِذْ نَزَلَ عَلَيْهِ ‏{‏وَالْمُرْسَلاَتِ‏}‏ وَإِنَّهُ لَيَتْلُوهَا، وَإِنِّي لأَتَلَقَّاهَا مِنْ فِيهِ، وَإِنَّ فَاهُ لَرَطْبٌ بِهَا، إِذْ وَثَبَتْ عَلَيْنَا حَيَّةٌ فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ اقْتُلُوهَا ‏"‏‏.‏ فَابْتَدَرْنَاهَا، فَذَهَبَتْ، فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ وُقِيَتْ شَرَّكُمْ كَمَا وُقِيتُمْ شَرَّهَا ‏"‏‏.‏