A divinely authored text, one would assume, would either correct this odd idea, or at least ignore it. The Qur’an, however, does neither: it uncritically repeats it.
So have they not travelled through the earth and have hearts by which to reason and ears by which to hear? For indeed, it is not eyes that are blinded, but blinded are the hearts which are within the breasts.
Qur’an 22:46
Here the heart is described as the place of reason, the organ producing thought. It is not allegorical, because it is plainly mentioned on the same plane as ears: the heart is for reasoning, the ears for hearing.
The same again here:
And We have certainly created for Hell many of the jinn and mankind. They have hearts with which they do not understand, they have eyes with which they do not see, and they have ears with which they do not hear. Those are like livestock; rather, they are more astray. It is they who are the heedless.
Qur’an 7:179
Again, the heart is the organ responsible for reasoning and understanding, in exactly the same way as eyes are for seeing and ears for hearing. Again, therefore, any allegorical reading is ruled out by the text.
The theologically absurd idea that God creates things specifically for hell is also a recurring theme in the Qur’an, but that is another topic.
A similar idea is also expressed in these two verses:
Unquestionably, they the disbelievers turn away their breasts to hide themselves from Him. Unquestionably, [even] when they cover themselves in their clothing, Allah knows what they conceal and what they declare. Indeed, He is knowing of that within the breasts.
Qur’an 11:5
Here you are loving them but they are not loving you, while you believe in the Scripture - all of it. And when they meet you, they say, "We believe." But when they are alone, they bite their fingertips at you in rage. Say, "Die in your rage. Indeed, Allah is knowing of that within the breasts."
Qur’an 3:119
In both verses it is held that “within the breasts” are found thought and intentions.
So, as in many previous examples, this shows that The Qur’an does not, by a very long way, stand up to its own claim of having divine authorship.