(47) باب الْكُحْلِ لِلْحَادَّةِ
Narrated Um Habiba:
The Prophet (ﷺ) said, "It is not lawful for a Muslim woman who believes in Allah and the Last Day to mourn for more than three days, except for her husband, for whom she should mourn for fourmonths and ten days."
Reference: Sahih al-Bukhari 5339
In-book reference: Book 68, Hadith 84
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 63, Hadith 252