Sahih al-Bukhari, Hadith 1280 ⓘ
Narrated Zainab bint Abi Salama: When the news of the death of Abu Sufyan reached from Sham, Um Habiba on the third day, asked for a yellow perfume and scented her cheeks and forearms and said, "No doubt, I would not have been in need of this, had I not heard the Prophet saying: "It is not legal for a woman who believes in Allah and the Last Day to mourn for more than three days for any dead person except her husband, for whom she should mourn for four months and ten days."
حَدَّثَنَا الْحُمَيْدِيُّ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا أَيُّوبُ بْنُ مُوسَى، قَالَ أَخْبَرَنِي حُمَيْدُ بْنُ نَافِعٍ، عَنْ زَيْنَبَ ابْنَةِ أَبِي سَلَمَةَ، قَالَتْ لَمَّا جَاءَ نَعْىُ أَبِي سُفْيَانَ مِنَ الشَّأْمِ دَعَتْ أُمُّ حَبِيبَةَ ـ رضى الله عنها ـ بِصُفْرَةٍ فِي الْيَوْمِ الثَّالِثِ، فَمَسَحَتْ عَارِضَيْهَا وَذِرَاعَيْهَا وَقَالَتْ إِنِّي كُنْتُ عَنْ هَذَا لَغَنِيَّةً، لَوْلاَ أَنِّي سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ " لاَ يَحِلُّ لاِمْرَأَةٍ تُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ أَنْ تُحِدَّ عَلَى مَيِّتٍ فَوْقَ ثَلاَثٍ، إِلاَّ عَلَى زَوْجٍ، فَإِنَّهَا تُحِدُّ عَلَيْهِ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا " .
also referenced under: Book 23, Hadith 42 (In-Book) & Volume 2, Book 23, Hadith 370 (USC-MSA)