(Qasas) 28 : 32
اسْلُكْ يَدَكَ فِي جَيْبِكَ تَخْرُجْ بَيْضَاءَ مِنْ غَيْرِ سُوءٍ وَاضْمُمْ إِلَيْكَ جَنَاحَكَ مِنَ الرَّهْبِ ۖ فَذَانِكَ بُرْهَانَانِ مِنْ رَبِّكَ إِلَىٰ فِرْعَوْنَ وَمَلَئِهِ ۚ إِنَّهُمْ كَانُوا قَوْمًا فَاسِقِينَ
“Insert your hand into the pockets of your garment, it will come out as white without evil; and draw your arm close to you free from fear, thus those are two proofs from your Lord to Pharaoh and his chiefs. Indeed they have become a transgressing people”.
See explanation 17: 17; 18: 14-15 and 27: 12.