Sahih Muslim Book 43, Hadith Number 7174.
Chapter : Not known.
Ubaidullah b. ‘Abdullah b. ‘Utba reported: Ibn Abbas said to me: Do you know-and in the words of Harun (another narrator): Are you aware of-the last Sura which was revealed in the Qur’an as a whole? I said: Yes, “When came the help from Allah and the victory” (cx.). Thereupon, he said: You have told the truth. And in the narration of Abu Shaiba (the words are): Do you know the Sura? And he did not mention the words “the last one”.