"It is not permissible for a woman to mourn for anyone who dies for more than three days, except for her husband."
Sunan an-Nasa'i Book 27, Hadith 137
← Previous Hadith "She should have a Mahr like that of women like her, no less and no more; she has to observe the 'Iddah, and she is entitled to inherit." Ma'qil bin Sinan Al-Ashja'i stood up and said: "The Messenger of Allah passed a similar judgment among us concerning Birwa' bint Washiq." And Ibn Masud rejoiced at that.

Sunan an-Nasa'i Book 27, Hadith 136 Next Hadith → "It is not permissible for a woman who believes in Allah and the Last Day to mourn for more than three days, except for her husband."

Sunan an-Nasa'i Book 27, Hadith 138