And We had certainly brought them a Book which We detailed by (7:52)

Almuntakhab Fi Tafsir Alquran Alkarim

We send down a Book expounding and distinctly expressing the sum of what is vaguely known and what is unknown and with the divine knowledge implying firm belief of what is true on sufficient grounds, a Book based on Our Omniscience of the whole and of all in all, serving as a guide and a mercy to those whose hearts have been touched with the divine hand

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

(7:52) Surely We have brought them a Book which We expounded with knowledge; *36 a guidance and a mercy to those who believe '  *37

And We had certainly brought them a Book which We detailed by meaning

*36). The Qur'an has spelled out in some detail what constitutes the fundamental reality, explained the attitude that man ought to adopt, and laid down the fundarnentals of the way of life that he ought to follow. The tails laid down in the Book in this regard are based on sound knowledge rather than on conjecture and fancy.
*37). The contents and teachings of the Book are perspicuous enough to show one the right way. Moreover, the life-style of those who believe in this Book also bears out, by the beneficial effects it produces on human life, how well it guides man. The blessings of the Qur'an become evident if man first notes the healthy changes that it brings about in his outlook, character and morals.
The above verse in fact alludes to the wonderful effect belief in the Qur'an had on the lives of the Companions of the Prophet (peace be on him).
 

And We had certainly brought them a Book which We detailed by meaning in Urdu

ہم اِن لوگوں کے پاس ایک ایسی کتاب لے آئے ہیں جس کو ہم نے علم کی بنا پر مفصل بنایا ہے اور جو ایمان لانے والوں کے لیے ہدایت اور رحمت ہے