The pronoun in the Saying of Allah:

﴿يُضِلُّ مَنْ يَشَآءُ وَيَهْدِى مَنْ يَشَآءُ﴾

[which means] “He misguides whomever He Willed and He guides whomever He Willed,” goes back to Allah; it does not go back to the slave as was claimed by the deniers of the Qadar. This is proven by the Saying of Allah the Exalted, informing about what our Master Musa said:

﴿إِنْ هِىَ إِلَّا فِتْنَتُكَ تُضِلُّ بِـهَا مَنْ تَشَآءُ وَتَـهْدِى مَنْ تَشَآءُ﴾

[which means] “Certainly that issue is the fitnah that was created by You, O Allah. You misguide by that fitnah whomever You Willed and You Guide whomever You Will.”