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."
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 454
Arabic reference: Book 65, Hadith 4931