وَقَالَ فِرْعَوْنُ ذَرُونِىٓ أَقْتُلْ مُوسَىٰ وَلْيَدْعُ رَبَّهُۥٓ ۖ إِنِّىٓ أَخَافُ أَن يُبَدِّلَ دِينَكُمْ أَوْ أَن يُظْهِرَ فِى ٱلْأَرْضِ ٱلْفَسَادَ Qur’an Ghafir (40:26)Waq a la firAAawnu th aroonee aqtul moos a walyadAAu rabbahu innee akh a fu an yubaddila deenakum aw an yu th hira fee alar d i alfas a d a
My interpolation of the word "alleged", is necessitated by the obvious sarcasm of Pharaoh's remark.
This is an episode that occurs when Moses, invested with his mission, confronts Pharaoh in his Court and preaches to him: see xx. 49 and following verses; also xx. 57, 63.
Some of Pharaoh's people did afterwards give up the worship of Pharaoh and of the Egyptian gods and believed "in the Lord of Aaron and Moses" and in fact suffered martyrdom for the Faith of Unity: xx. 70-73.