﴿ قَالَ أَلْقُوا۟ ۖ فَلَمَّآ أَلْقَوْا۟ سَحَرُوٓا۟ أَعْيُنَ ٱلنَّاسِ وَٱسْتَرْهَبُوهُمْ وَجَآءُو بِسِحْرٍ عَظِيمٍۢ ﴾

“He answered: "You throw [first]." And when they threw down [their staffs], they cast a spell upon the people's eyes, and struck them with awe, and produced mighty sorcery.”

He said ‘Cast!’ this is a command permitting them to cast first as a means to manifesting the truth. And when they cast their ropes and staffs they put a spell upon the people’s eyes misleading them from perceiving the real state of these ropes and staffs and overawed them scared them by making them appear to be slithering snakes and produced a mighty sorcery.