Narrated Ibn 'Abbas:
that the Messenger of Allah (ﷺ) said: "When Allah drowned Fir'awn he said: 'I believe that there is no god except the One that the children of Isra'il believe in.' So Jibrail said: 'O Muhammad! If you could only have seen me, while I was taking (the mud) from the sea, and filling his mouth out of fear that the mercy would reach him.'" (TH)
English reference (TH): Vol. 5, Book 44, Hadith 3107 (TH)
Arabic reference (TH): Book 47, Hadith 3392 (TH)