قَالَ فِرْعَوْنُ ءَامَنتُم بِهِۦ قَبْلَ أَنْ ءَاذَنَ لَكُمْ ۖ إِنَّ هَـٰذَا لَمَكْرٌ مَّكَرْتُمُوهُ فِى ٱلْمَدِينَةِ لِتُخْرِجُوا۟ مِنْهَآ أَهْلَهَا ۖ فَسَوْفَ تَعْلَمُونَ
Qaala Fir'awnu aamantum bihee qabla an aazana lakum; inna haaza lamakrum makartumoohu filmadeenati litukhrijoo minhaaa ahlahaa fasawfa ta'almoon
Pharaoh said, "You have believed in him before I gave you permission? This is surely a scheme you plotted in the city to drive its people out. Soon you will know.
Pharaoh meets a conversion by raising a question of permission: the sorcerers believed before he authorised it. Only then does he reach for a conspiracy, accusing them of arranging the contest with Musa in order to take the city from its people, a charge the story has already answered, since Pharaoh was the one who summoned them. The threat that follows concedes the argument is lost.