In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Allaah [The Most High] informs us in Surah Al-A’raaf Aayaat 123-126 that Fir’awn threatened the sorcerers after they abandoned their misguidance and accepted Moosaa’s [alayhis-salaam] message; Allaah [The Most High] says that Fir’awn said to them: [ءَامَنتُم بِهِۦ قَبۡلَ أَنۡ ءَاذَنَ لَكُم – You have believed in him [Musa (Moses)] before I give you permission]; Fir’awn- the cruel and opinionated judge- considered himself as the only one deserving of passing judgements on the statements of the people and in the assemblies. It was established by him and accepted by his people that he was the one to be followed and no one was allowed to oppose his judgements and statements. Therefore, contradicting his judgements and statements is tantamount to bad behaviour and disrespect.
Then Allaah [The Most High] says that Firawn said to His people: [إِنَّ هَـٰذَا لَمَكۡرٌ۬ مَّكَرۡتُمُوهُ فِى ٱلۡمَدِينَةِ لِتُخۡرِجُواْ مِنۡہَآ أَهۡلَهَاۖ فَسَوۡفَ تَعۡلَمُونَ – Surely, this is a plot which you have plotted in the city to drive out its people, but you shall come to know]; meaning: Fir’awn claimed that Moosaa [alayhis-salaam] is the elder (or leader) of the sorcerers who taught them sorcery and the sorcerers secretly allowed him to be victorious, so that the majority of people will follow them. This is an outright lie and Fir’awn was absolutely certain of it! Indeed, Moosaa [alayhis-salaam] never sought the support of the sorcerers; rather it was Fir’awn who sent his followers to the various cities of Egypt to gather the sorcerers to champion his cause. As for Moosaa [alayhis-salaam] he came with clear signs from Allaah [The Most High], whereas the sorcerers brought sorcery in order to defeat him; but their plot failed and the truth Moosaa [alayhis-salaam] brought became manifest to them, so they followed him.
Then Allaah [The Most High] says that Firawn said to those who repented from sorcery and believed in Moosaa: [لَأُقَطِّعَنَّ أَيۡدِيَكُمۡ وَأَرۡجُلَكُم مِّنۡ خِلَـٰفٍ۬ ثُمَّ لَأُصَلِّبَنَّكُمۡ أَجۡمَعِينَ -Surely, I will cut off your hands and your feet on opposite sides, then I will crucify you all]; Fir’awn- the cruel one- claimed that those who abandoned his way and followed the path of Moosaa [alayhis-salaam] were guilty of causing corruption in the earth and that he will deal with them in that manner in which such people deserve to be dealt with.
Then Allaah [The Most High] says that those who repented from sorcery and followed Moosaa [alayhis-salaam] replied to Fir’awn, saying: [إِنَّآ إِلَىٰ رَبِّنَا مُنقَلِبُونَ – Verily, we are returning to our Lord!] [وَمَا تَنقِمُ مِنَّآ إِلَّآ أَنۡ ءَامَنَّا بِـَٔايَـٰتِ رَبِّنَا لَمَّا جَآءَتۡنَاۚ رَبَّنَآ أَفۡرِغۡ عَلَيۡنَا صَبۡرً۬ا وَتَوَفَّنَا مُسۡلِمِي ]- And you take vengeance on us only because we believed in the Ayat (proofs, evidences, lessons, signs, etc.) of our Lord when they reached us! Our Lord! pour out on us patience, and cause us to die as Muslims].
[Source: An Excerpt from ‘Tayseer Al-Kareem Ar-Rahmaan Fee Tafseer Kalaam Al-Mannaan’ by Imaam As-Sadi (rahimahullaah)]