Commentary
This Surah is Makki, although Muqatil رحمۃ اللہ علیہ has said that the verse وَاسْأَلْ مَنْ أَرْسَلْنَا (43:45) is Madam, and according to another view, this Surah was revealed in Heaven during Lailat-ul-Mi` raj (the Night of Ascention) (Ruh u1-Ma’ ani) - Allah knows best.
Ha Meem- Only Allah knows its meaning.
وَالْكِتَابِ الْمُبِينِ (By the manifest Book - 43:2) The book in this verse refers to the Holy Qur'an. Whenever Allah swears by anything, it is usually an argument for the statement that follows. Swearing by the Qur'an in this verse is an indication that the Qur'an, by virtue of being a miracle, is a proof in itself of its being a Divine Book. To call it a 'manifest book' means that its subjects consisting of exhortations and advices are easily understandable; but as far as deduction of the precepts of 'Shari'ah' is concerned, it certainly is a difficult job which cannot be performed without complete capability of 'ijtihad'. This point has been clarified in Surah Alqamar, verse 17 وَلَقَدْ يَسَّرْنَا الْقُرْآنَ لِلذِّكْرِ فَهَلْ مِن مُّدَّكِرٍ (And indeed We have made the Qur'an easy for seeking advice. So, is there one to seek advice? - 54-17). Here, it has been stated that the Qur'an is easy for obtaining advice. Hence, it does not necessarily follow that ijtihad and inferring injunctions will be easy also; rather, it is proved through other evidences that full expertise in related subjects is a necessary condition for this exercise.