The Day of Judgment: The Book of Deeds and the Fear of the Wrongdoers [Al Quran 18:49]

وَوُضِعَ ٱلۡكِتَـٰبُ فَتَرَى ٱلۡمُجۡرِمِینَ مُشۡفِقِینَ مِمَّا فِیهِ وَیَقُولُونَ یَـٰوَیۡلَتَنَا مَالِ هَـٰذَا ٱلۡكِتَـٰبِ لَا یُغَادِرُ صَغِیرَةࣰ وَلَا كَبِیرَةً إِلَّاۤ أَحۡصَىٰهَاۚ وَوَجَدُوا۟ مَا عَمِلُوا۟ حَاضِرࣰاۗ وَلَا یَظۡلِمُ رَبُّكَ أَحَدࣰا

And the Book was placed, so you see the criminals fearful of what is in it and they say, "Woe to us! What is this book that does not leave a small thing or a big thing except that it has counted it?" And they found what they did present. And your Lord does not wrong anyone.

Having brought the scene forward to give it an added sense of reality, the sūrah resumes its description of what takes place there: 

وَوُضِعَ ٱلۡكِتَـٰبُ - And the Book was placed

فَتَرَى ٱلۡمُجۡرِمِینَ مُشۡفِقِینَ مِمَّا فِیهِ - so you see the criminals fearful of what is in it

It is the record of all their deeds placed before their eyes to read and review. They realize that it is a comprehensive and accurate record, and they fear the consequences. They are embarrassed by the fact that the record includes every single thing, no matter how small or trivial. In their frustration, they exclaim: 

وَیَقُولُونَ یَـٰوَیۡلَتَنَا - and they say, "Woe to us!

مَالِ هَـٰذَا ٱلۡكِتَـٰبِ - What is this book

لَا یُغَادِرُ صَغِیرَةࣰ وَلَا كَبِیرَةً إِلَّاۤ أَحۡصَىٰهَاۚ - that does not leave a small thing or a big thing except that it has counted it?"

This is the cry of one who is worried, fearing the worst after he has been caught red-handed, unable to evade the results or find any justification. This is because he recognizes the accuracy of the record which puts before his eyes all that he has done:

وَوَجَدُوا۟ مَا عَمِلُوا۟ حَاضِرࣰاۗ - And they found what they did present.

They also realize that whatever befalls them will only be fair, because -

وَلَا یَظۡلِمُ رَبُّكَ أَحَدࣰا - And your Lord does not wrong anyone.

By - Syed Qutb: Fi Zilalil Quran