We discussed the individual letters at the beginning of Surat Al-Baqarah, and there is no need to repeat it here.

﴿تَنزِيلُ الْكِتَـبِ لاَ رَيْبَ فِيهِ﴾

(The revelation of the Book in which there is no doubt,) means, there is no doubt whatsoever that it has been revealed

﴿مِّن رَّبِّ الْعَـلَمِينَ﴾

(from the Lord of all that exists.) Then Allah tells us about the idolators:

﴿أَمْ يَقُولُونَ افْتَرَاهُ﴾

(Or say they: "He has fabricated it''): they say, he has fabricated it, i.e., he has made it up by himself.

﴿بَلْ هُوَ الْحَقُّ مِن رَّبِّكَ لِتُنذِرَ قَوْماً مَّآ أَتَـهُم مِّن نَّذِيرٍ مِّن قَبْلِكَ لَعَلَّهُمْ يَهْتَدُونَ﴾

(Nay, it is the truth from your Lord, so that you may warn a people to whom no warner has come before you, in order that they may be guided.) means, in order that they may follow the truth.

﴿اللَّهُ الَّذِى خَلَقَ السَّمَـوَتِ وَالاٌّرْضَ وَمَا بَيْنَهُمَا فِى سِتَّةِ أَيَّامٍ ثُمَّ اسْتَوَى عَلَى الْعَرْشِ مَا لَكُمْ مِّن دُونِهِ مِن وَلِيٍّ وَلاَ شَفِيعٍ أَفَلاَ تَتَذَكَّرُونَ - يُدَبِّرُ الاٌّمْرَ مِنَ السَّمَآءِ إِلَى الاٌّرْضِ ثُمَّ يَعْرُجُ إِلَيْهِ فِى يَوْمٍ كَانَ مِقْدَارُهُ أَلْفَ سَنَةٍ مِّمَّا تَعُدُّونَ - ذَلِكَ عَالِمُ الْغَيْبِ وَالشَّهَـدَةِ الْعَزِيزُ الرَّحِيمُ ﴾

(4. Allah it is He Who has created the heavens and the earth, and all that is between them in six Days. Then He Istawa over the Throne. You have none, besides Him, as a protector or an intercessor. Will you not then remember) (5. He directs the command from the heavens to the earth; then it will go up to Him, in one Day, the space whereof is a thousand years of your reckoning.) (6. That is He, the All-Knower of the unseen and the seen, the All-Mighty, the Most Merciful.)