﴿ فَأَوْجَسَ فِى نَفْسِهِۦ خِيفَةًۭ مُّوسَىٰ ﴾

“and in his heart Moses became apprehensive.”

(And Moses conceived a fear in his mind) Moses concealed his fear of them. He was afraid that they would kill all those who believed in him, if he failed to defeat them.