And they did not estimate Allah with the estimation due to Him when they said, “”Allah did not send down anything on man.”” Say, “”Who (then) sent down the book with which Musa had come, (in which there was) light and guidance for mankind, of which you have made (written) pages, (part of) which you manifest while you hide much, and (through which) you were taught that which you did not know, you and your forefathers?”” Say, “”Allah,”” then leave them sporting in their involvement (of vain talk).
People probably commented that it was not possible for Muhammed (PBH), a man, to receive the Quran from Allah (SWT). Therefore they are asked as to who had revealed the Torah to Musa (PBH). Then it is clarified that the Quran, confirming earlier Divine revelations was revealed by Allah (SWT), first to warn the Makkans and later to its surroundings extending to the whole world as Makkah is more or less centrally located with respect to all the continents.