Musnad Ahmad 4305

It was narrated that Ibn Mas'ood said: We were with the Messenger of Allah (ﷺ) on the slope of a mountain. He was standing and praying, and they were sleeping. Then a snake passed by him and we woke up as he was saying: "The One who protected it from you is the One Who protected you from it.” And the soorah "By the winds (or angels or the Messengers of Allah) sent forth one after another. And by the winds that blow violently" (al-Mursalat 77:1–2) was revealed to him, and we learned it fresh from his lips.