3533b. Sunan an-Nasa’i Chapter: Divorce At The Time When Allah Has Stated That Women May Be Divorced; Book 27, Hadith 146

Zainab said: “Then I went into Zainab bint Jahsh when her brother died, and she called for some perfume and put some on. Then she said: ‘By Allah, I do not have any need for perfume but I heard the Messenger of Allah say on the Minbar: It is not permissible for any woman who believes in Allah and the Last Day to mourn for anyone who dies for more than three days, except for a husband, (for whom the mourning period is) four months and ten days.’”