مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3130
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn ‘Abbas (رضي الله عنه) said, and one of them (the narrators] attributed it to The Prophet (ﷺ): "Jibreel was shoving mud into Pharaoh's mouth for fear that he would say, La ilaha iIlallah."
Musnad Ahmad 3154Saheeh mawqoof; the isnad stops with Ibn 'Abbas]