On the Day when We shall strike you with the great Batshah. Verily, We will exact retribution.Ibn Mas`ud interpreted this to mean the day of Badr.This is also the view of a group who agreed with Ibn Mas`ud, may Allah be pleased with him, about the meaning of the smoke, as discussed above.It was also narrated from Ibn Abbas, may Allah be pleased with him, in a report related to him from Al-`Awfi and from Ubayy bin Ka`b, may Allah be pleased with him.This is possible, but the apparent meaning is that it refers to the Day of Resurrection, although the day of Badr was also a day of vengeance.Ibn Jarir said, "Ya`qub narrated to me; Ibn `Ulayyah narrated to me, Khalid Al-Hadhdha' narrated to us, from Ikrimah who said, Ibn Abbas, may Allah be pleased with him, said,"Ibn Mas`ud, may Allah be pleased with him, said that;"the great Batshah" is the day of Badr, and I say that it is the Day of Resurrection."This chain of narration is Sahih to him.This is also the view of Al-Hasan Al-Basri and of Ikrimah according to the more authentic of the two reports narrated from him. And Allah knows best