Sunan an-Nasa'i 3504
سنن النسائي#3504Sahihأَخْبَرَنَا عَبْدُ اللَّهِ بْنُ الصَّبَّاحِ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ سَوَاءٍ، قَالَ أَنْبَأَنَا سَعِيدٌ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنْ صَفِيَّةَ بِنْتِ أَبِي عُبَيْدٍ، عَنْ بَعْضِ، أَزْوَاجِ النَّبِيِّ صلى الله عليه وسلم وَعَنْ أُمِّ سَلَمَةَ أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " لاَ يَحِلُّ لاِمْرَأَةٍ تُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ تَحِدُّ عَلَى مَيِّتٍ أَكْثَرَ مِنْ ثَلاَثَةِ أَيَّامٍ إِلاَّ عَلَى زَوْجٍ فَإِنَّهَا تَحِدُّ عَلَيْهِ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا " .
It was narrated from Safiyyah bint Abi 'Ubaid from one of the wives of the Prophet, and from Umm Salamah, that the Prophet said:"It is not permissible for a woman who believes in Allah and the Last Day to mourn for anyone who dies for more than three days except for a husband; she should mourn for him for four months and ten (days)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 27:116