Which was revealed in Makkah
In Musnad Al-Bazzar, it is recorded from Abu At-Tufayl `Amir bin Wathilah from Zayd bin Harithah that the Messenger of Allah ﷺ said to Ibn Sayyad:
«إِنِّي قَدْ خَبَأْتُ خَبْأً فَمَا هُوَ؟»
(I am concealing something, what is it) And the Messenger of Allah ﷺ was concealing Surat Ad-Dukhan from him. He (Ibn Sayyad) said: "It is Ad-Dukh." The Messenger of Allah ﷺ said,
«اخْسَأْ مَا شَاءَ اللهُ (كَانَ)»
(Be off with you! Whatever Allah wills happens.)
بِسْمِ اللَّهِ الرَّحْمَـنِ الرَّحِيمِ
In the Name of Allah, the Most Gracious, the Most Merciful.
The Qur'an was revealed on Laylatul-Qadr
Allah tells us that He revealed the Magnificent Qur'an on a blessed night, Laylatul-Qadr (the Night of Decree), as He says elsewhere:
Continue reading the tafsir of ayahs 1–8Ma'arif al-Qur'an
Mufti Muhammad Shafi
Commentary
The Merit of the Surah
Sayyidna Abu Hurairah رضی اللہ تعالیٰ عنہ reports that the Messenger of Allah ﷺ said that whoever recites Surah Dukhan on Friday night, his sins will have been forgiven by the morning. Sayyidna Umamah ؓ narrates that the Messenger of Allah ﷺ said anyone who recites Surah Dukhan on Friday, in the night or in the day, Allah will build for him a house in Paradise. (Qurtubi on the authority of Thalabi).
In the present set of verses, the greatness of Qur'an and some of its special features are described. وَالْكِتَابِ الْمُبِينِ "By the manifest Book". This verse refers to the Holy 'Qur'an'. In the verse Allah swears an oath by the magnificent Qur'an to state that it was revealed in a blessed and auspicious Night, the purpose of which is to awaken the unmindful human beings from their deep slumber. A similar oath was taken, in exactly the same words, at the commencement of Surah Az-Zukhruf (Chapter 43). The oath-phrase has been fully discussed there.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.