(50) بَابُ: {وَالَّذِينَ يُتَوَفَّوْنَ مِنْكُمْ وَيَذَرُونَ أَزْوَاجًا} إِلَى قَوْلِهِ: {بِمَا تَعْمَلُونَ خَبِيرٌ}
Narrated Zainab bint Um Salama:
When Um Habiba bint Abi Sufyan was informed of her father's death, she asked for perfume and rubbed it over her arms and said, "I am not in need of perfume, but I have heard the Prophet (ﷺ) saying, "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 the (mourning) period is four months and ten days."
Reference: Sahih al-Bukhari 5345
In-book reference: Book 68, Hadith 90
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 63, Hadith 257