(58) باب الإِحْدَادِ
It was narrated from 'Aishah that the Messenger of Allah said:
"It is not permissible for a woman to mourn for anyone who dies for more than three days, except for her husband."
Reference: Sunan an-Nasa'i 3525
In-book reference: Book 27, Hadith 137
English translation: Vol. 4, Book 27, Hadith 3555