The subject matter of this Surah indicates that it was revealed during the last stage of the Holy Prophet's residence at Makkah, when the Quraish were considering the question of killing or exiling or imprisoning him. At that time some of the unbelievers put this question (probably at the instigation of the Jews) to test him :'Why did the Israelites go to Egypt?'' This question was asked because they knew that their story was not known to the Arabs for there was no mention of it whatever in their traditions and the Holy Prophet had never even referred to it before.