(46) باب تُحِدُّ الْمُتَوَفَّى عَنْهَا زَوْجُهَا أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا
Zainab further said:
I want to Zainab bint Jahsh when her brother died. She asked for perfume and used some of it and said, "By Allah, I am not in need of perfume, but I have heard Allah's Messenger (ﷺ) saying on the pulpit, 'It is not lawful for a lady 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 four months and ten days.'"
Reference: Sahih al-Bukhari 5335
In-book reference: Book 68, Hadith 80
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 63, Hadith 251