Prophet Hud - 11:91
"Shu´ayb,"they said, "we do not understand much of what you say. Moreover, we consider you weak among us. If it were not for your tribe, we would have stoned you. You have no superiority over us."
Why don't they understand?
The Cattle/6:110
We turn away their understanding and their eyes and leave them floundering in their rebellion because they decided not to believe at first.
The Cattle/6:111
And if We send down to them angels, and the dead speak to them, and We bring everything before them, they will not believe, except those whom Allah wills. But most of them do not know this truth.
The Women/4:155
"Allah sealed their understanding because of their breaking their word, because they disbelieved in the signs and proofs of Allah, because they killed the prophets unjustly, and because they said: "We are fixed-minded", yes, because of their disbelief. Therefore few of them believe."
The Heights/7:146
I will turn away from My miracles those who are unjustly arrogant in the earth. Even if they see all kinds of miracles, they will not believe. If they see the right path, they do not follow it. But if they see the way of transgression, they follow it. For they denied Our Verses and paid no heed.
Prophet Jonah/10:96
Those who are condemned by the decision of their Lord do not believe.
Prophet Jonah/10:97
Even if all kinds of miracles come to them, they will not believe until they see the painful torment.
The Hypocrites/63:3
Because they disbelieved after they believed, so their hearts were sealed; they do not understand.
The Kneeling/45:23
Have you paid attention to him who takes his desire as a god? Allah has deliberately led him astray, and has sealed his hearing and his brain and put a veil over his sight. Who can guide him to the truth except Allah? Do you not take admonition?