﴿ قَالُوا۟ يَٰمُوسَىٰٓ إِمَّآ أَن تُلْقِىَ وَإِمَّآ أَن نَّكُونَ أَوَّلَ مَنْ أَلْقَىٰ ﴾

“Said [the sorcerers]: "O Moses! Either thou throw (thy staff first], or we shall be the first to throw."”

فَأَجْمِعُوا كَيْدَكُمْ ثُمَّ ائْتُوا صَفًّا (So, make your plot firm and forth in one row - 20:64). Formation of troops in ranks in battle has an unsettling effect on the enemy, so the Egyptian magicians arranged themselves in ranks for the contest.