قَالَ ءَامَنتُمْ لَهُۥ قَبْلَ أَنْ ءَاذَنَ لَكُمْ ۖ إِنَّهُۥ لَكَبِيرُكُمُ ٱلَّذِى عَلَّمَكُمُ ٱلسِّحْرَ فَلَسَوْفَ تَعْلَمُونَ ۚ لَأُقَطِّعَنَّ أَيْدِيَكُمْ وَأَرْجُلَكُم مِّنْ خِلَـٰفٍ وَلَأُصَلِّبَنَّكُمْ أَجْمَعِينَ Qur’an Ash-Shuara (26:49)Qala amantum lahu qabla an athana lakum innahu lakabeerukumu allathee AAallamakumu alssihra falasawfa taAAlamoona laoqattiAAanna aydiyakum waarjulakum min khilafin walaosallibannakum ajmaAAeena
See note [91] on 7:123 .
I.e., "he is so superior a sorcerer that he could be your teacher".
See notes [44] and [45] on {5: 33}, and note [92] on 7:124 , which explain the repeated stress on "great numbers" in the above sentence.
The sorcerers knew that they had met something very different from their tricks. Allah's power worked on them and they professed the True God. As they represented the intelligence of the community, it may be presumed that they carried the intelligence of Egypt with them and perhaps some of the commonalty, who were impressed by the dramatic scene! Hence Pharaoh's anger, but it is the beginning of his decline!