Is the saying of Allah the Exalted, "Is not Allah most knowing of the grateful ones," from the speech of Allah or from the speech of the polytheists?

Question:
May Allah reward you, Your Eminence, father. This questioner says: In the saying of Allah the Exalted, , is this from the saying of Allah the Exalted, or is it part of the saying of the polytheists?

Answer:
The polytheists say, "Allah knows best who the grateful ones are." This is from the speech of Allah, Mighty and Majestic, in response to them, a response to the polytheists. Yes.