Verily, those who 'Yulḥidūna Fī' Our Ayat are not hidden from Us. Is he who is cast into the Fire better or he who comes secure on the Day of Resurrection? Do what you will. Verily, He is All-Seer of what you do (40)Verily, those who disbelieved in the Reminder when it came to them. And verily, it is an honorable well-fortified respected Book (41)Falsehood cannot come to it from before it or behind it, (it is) sent down by the All-Wise, Worthy of all praise (42)Nothing is said to you except what was said to the Messengers before you. Verily, your Lord is the Possessor of forgiveness, and (also) the Possessor of painful punishment (43)

The Punishment of the Deniers and the Description of the Qur'an

إِنَّ الَّذِينَ يُلْحِدُونَ فِي آيَاتِنَا 

(Verily, 'Yulḥidūna Fī' Our Ayat) Ibn 'Abbas said, "Al-Ilḥād means putting words in their improper places." Qatadah and others said, "It means disbelief and obstinate behavior."

 لَا يَخْفَوْنَ عَلَيْنَا

(are not hidden from Us.) This is a stern warning and dire threat, stating that He, may He be exalted, knows who denies His signs, Names and attributes, and He will punish them for that. He says:

أَفَمَنْ يُلْقَىٰ فِي النَّارِ خَيْرٌ أَمْ مَنْ يَأْتِي آمِنًا يَوْمَ الْقِيَامَةِ ۚ 

(Is he who is cast into the Fire better or he who comes secure on the Day of Resurrection?) means, are these two equal? They are not equal. Then Allah warns the disbelievers:

اعْمَلُوا مَا شِئْتُمْ 

(Do what you will.) Mujahid, Ad-Dahhak and 'Ata' Al-Khurasani said that

اعْمَلُوا مَا شِئْتُمْ 

(Do what you will.) is a threat. Meaning, 'do what you will of good or evil, for He knows and sees all that you do.' He says:

إِنَّهُ بِمَا تَعْمَلُونَ بَصِيرٌ 

(Verily, He is All-Seer of what you do.)

إِنَّ الَّذِينَ كَفَرُوا بِالذِّكْرِ لَمَّا جَاءَهُمْ ۖ 

(Verily, those who disbelieved in the Reminder when it came to them.) Ad-Dahhak, As-Suddi and Qatadah said, "This is the Qur'an."

وَإِنَّهُ لَكِتَابٌ عَزِيزٌ

(And verily, it is an honorable well-fortified respected Book.) means, it is protected and preserved, and nobody can produce anything like it.

لَا يَأْتِيهِ الْبَاطِلُ مِنْ بَيْنِ يَدَيْهِ وَلَا مِنْ خَلْفِهِ ۖ 

(Falsehood cannot come to it from before it or behind it,) means, there is no way to corrupt it, because it has been sent down by the Lord of the worlds. Allah says:

تَنْزِيلٌ مِنْ حَكِيمٍ حَمِيدٍ

((it is) sent down by the All-Wise, Worthy of all praise.) meaning, He is Wise in all that He says and does, Praiseworthy in all that He commands and forbids; everything that He does is for praiseworthy purposes and its consequences will be good.

مَا يُقَالُ لَكَ إِلَّا مَا قَدْ قِيلَ لِلرُّسُلِ مِنْ قَبْلِكَ ۚ 

(Nothing is said to you except what was said to the Messengers before you.) Qatadah, As-Suddi and others said, "Nothing is said to you by way of rejection and disbelief, that was not said to the Messengers who came before you. Just as you have been rejected, they were also rejected. Just as they bore their people's insults with patience, so too you must bear your people's insults with patience."

إِنَّ رَبَّكَ لَذُو مَغْفِرَةٍ

(Verily, your Lord is the Possessor of forgiveness,) means, for those who turn to Him in repentance.

وَذُو عِقَابٍ أَلِيمٍ

(and (also) the Possessor of painful punishment.) means, for those who persist in disbelief, transgression and stubborn opposition.