The Surah derives its name Al-Ahzab from verse 20.
Period of Revelation
The Surah discusses three important events which are: the Battle of the Trench (or Al-Ahzab : the Clans), which took place in Shawwal, A. H. 5; the raid on Bani Quraizah, which was made in Dhil-Qa'dah, A. H. 5; and the Holy Prophet's marriage with Hadrat Zainab, which also was contracted in Dhil-Qa'dah, A. H. 5. These historical events accurately determine the period of the revelation of this Surah.
The Islamic army's setback in the Battle of Uhud (A. H. 3) that resulted from the error of the archers appointed by the Holy Prophet so boosted up the morale of the Arab pagans and the Jews and the hypocrites that they started entertaining the hope that they would soon be able to exterminate Islam and the Muslims completely. Their high state of morale can be judged from the events that occurred in the first year after Uhud. Hardly two months had passed then the tribe of Bani Asad of Najd beg