Narrated Said bin Jubair:
I asked Ibn Abbas about Surat Al-Tauba, and he said, "Surat Al-Tauba? It is exposure (of all the evils of the infidels and the hypocrites). And it continued revealing (that the oft-repeated expression): '...and of them ...and of them.' till they started thinking that none would be left unmentioned therein." I said, "What about) Surat Al-Anfal?" He replied, "Surat Al-Anfal was revealed in connection with the Badr Battle." I said, "(What about) Surat Al-Hashr?" He replied, "It was revealed in connection with Bani an-Nadir."
Sahih al-Bukhari, Vol. 6, Book of Prophetic Commentary on the Qur'an, Hadith 404
Sahih al-Bukhari, Book of Prophetic Commentary on the Qur'an, Hadith 404