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Surah 6. Al-An'am
Ayah 46 - 49
46قُلْ أَرَءَيْتُمْ إِنْ أَخَذَ ٱللَّهُ سَمْعَكُمْ وَأَبْصَـٰرَكُمْ وَخَتَمَ عَلَىٰ قُلُوبِكُم مَّنْ إِلَـٰهٌ غَيْرُ ٱللَّهِ يَأْتِيكُم بِهِ ۗ ٱنظُرْ كَيْفَ نُصَرِّفُ ٱلْـَٔايَـٰتِ ثُمَّ هُمْ يَصْدِفُونَ
47قُلْ أَرَءَيْتَكُمْ إِنْ أَتَىٰكُمْ عَذَابُ ٱللَّهِ بَغْتَةً أَوْ جَهْرَةً هَلْ يُهْلَكُ إِلَّا ٱلْقَوْمُ ٱلظَّـٰلِمُونَ
48وَمَا نُرْسِلُ ٱلْمُرْسَلِينَ إِلَّا مُبَشِّرِينَ وَمُنذِرِينَ ۖ فَمَنْ ءَامَنَ وَأَصْلَحَ فَلَا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ
49وَٱلَّذِينَ كَذَّبُوا۟ بِـَٔايَـٰتِنَا يَمَسُّهُمُ ٱلْعَذَابُ بِمَا كَانُوا۟ يَفْسُقُونَ
[46-49] O Muhammad, ask them, "Have you ever considered this: If Allah were to take away your hearing and your sight and set a seal upon your hearts,30 is there a deity other than Allah to restore them to you?" Behold! how We present Our Signs before them over and over again, and how they turn away from them in disdain. Say, "Have you also ever considered this: If the scourge of Allah comes upon you suddenly or openly, shall any but the transgressors be destroyed? For We send Our Messengers only to give good news to the righteous people and to warn the evil-doers: then those, who accept their Message and reform their own conduct, will have no cause for fear and sorrow and those who treat Our Revelations as false, shall have to suffer punishment in consequence of their evil deeds.
30"... and set a seal upon your hearts" means" ...deprive you of the powers of thinking and understanding.