Musnad Abu Ya'la al-Mawsili 151:4

Abu Khaythama narrated to us, Ibn 'Uyaynah narrated to us, from 'Asim, from Zirr, from 'Abdullah, who said: We were with the Prophet, may Allah bless him and grant him peace, in a cave when "By the emissaries, sent forth one after another" (Al-Mursalat) was revealed to him. I took it from his mouth, and his mouth was moist [with the revelation]. I do not know with which [verse] it ended: "Then in what message after it will they believe?" (Al-Mursalat), or "And when it is said to them, 'Bow,' they do not bow" (Al-Mursalat). Then a snake rushed past us and entered a hole. The Messenger of Allah, may Allah bless him and grant him peace, said: "You have been protected from its evil, and it has been protected from your evil."