هَذَا كِتَابُنَا يَنطِقُ عَلَيْكُم بِالْحَقِّ
...
This, Our Record speaks about you with truth.
It contains the record of all your actions, without addition or deletion.
Allah also said:
وَوُضِعَ الْكِتَـبُ فَتَرَى الْمُجْرِمِينَ مُشْفِقِينَ مِمَّا فِيهِ وَيَقُولُونَ يوَيْلَتَنَا مَا لِهَـذَا الْكِتَـبِ لاَ يُغَادِرُ صَغِيرَةً وَلاَ كَبِيرَةً إِلاَّ أَحْصَاهَا وَوَجَدُواْ مَا عَمِلُواْ حَاضِرًا وَلاَ يَظْلِمُ رَبُّكَ أَحَدًا
And the Book will be presented, and you will see the criminals, fearful of that which is therein. They will say:
"Woe to us! What sort of Book is this that leaves neither a small thing nor a big thing, but has recorded it with numbers!"
And they will find all that they did, placed before them, and your Lord treats no one with injustice. (18:49)
Allah's statement,
...
إِنَّا كُنَّا نَسْتَنسِخُ مَا كُنتُمْ تَعْمَلُونَ
Verily, We were recording what you used to do.
means, `We ordered Our scribe angels to record your deeds.'
Ibn Abbas and others commented,
"The angels record the deeds of the servants and then ascend to heaven with them. There, they meet the angels entrusted with the Records of deeds sent down from Al-Lawh Al-Mahfuz on each Night of Al-Qadr, containing what Allah has written will occur from the servants, long before He created them. They will compare their records and find out that not a single letter was added or deleted."
He then recited this Ayah,
إِنَّا كُنَّا نَسْتَنسِخُ مَا كُنتُمْ تَعْمَلُونَ
(Verily, We were recording what you used to do.