The revelation of the Book is from Allah, the Exalted in Might, (45:2)

Almuntakhab Fi Tafsir Alquran Alkarim

It -the Quran- is a Book that is emphatically revealed by Allah in complete glory, featuring Him as the guide, and who could be a better guide than Allah, AL-Aziz (the almighty), AL-Hakim (the Wise)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(45:2) This Book is a revelation from the Most Mighty, the Most Wise. *1

The revelation of the Book is from Allah, the Exalted in Might, meaning

*1) In this brief introduction to the Surah, the listeners have been warned of two things: (1) That this Book is not the composition of Muhammad (upon whom be Allah's peace) himself, but it is being sent down to him by Allah; and (2) that it is being sent down by that Allah Who is All-Mighty as well as All-Wise. His being the Almighty demands that man should not dare disobey His Commands, for if he disobeys Him, he cannot escape His punishment; and His being the All-Wise demands that man should obey and follow His Guidance and His Commands with full satisfaction and willingness of the heart, for there can be no possibility of His teachings being wrong or inadequate or harmful in any way.
 

The revelation of the Book is from Allah, the Exalted in Might, meaning in Urdu

اِس کتاب کا نزول اللہ کی طرف سے ہے جو زبردست اور حکیم ہے