Abu Dawud Book 8, Hadith Number 2665.
Chapter : Not known.
Narated By ‘Aisha, Ummul Mu’minin : No woman of Banu Qurayzah was killed except one. She was with me, talking and laughing on her back and belly (extremely), while the Apostle of Allah (PBUH) was killing her people with the swords. Suddenly a man called her name: Where is so-and-so? She said: I I asked: What is the matter with you? She said: I did a new act. She said: The man took her and beheaded her. She said: I will not forget that she was laughing extremely although she knew that she would be killed.