﴿ فَأَجْمِعُوا۟ كَيْدَكُمْ ثُمَّ ٱئْتُوا۟ صَفًّۭا ۚ وَقَدْ أَفْلَحَ ٱلْيَوْمَ مَنِ ٱسْتَعْلَىٰ ﴾

“Hence, [O sorcerers of Egypt,] decide upon the scheme which you will pursue, and then come forward in one single body: for, indeed, he who prevails today shall prosper indeed!"”

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.