Sunan an-Nasa'i 3541

أَخْبَرَنَا يَحْيَى بْنُ حَبِيبِ بْنِ عَرَبِيٍّ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ حُمَيْدِ بْنِ نَافِعٍ، عَنْ زَيْنَبَ، أَنَّ امْرَأَةً، سَأَلَتْ أُمَّ سَلَمَةَ وَأُمَّ حَبِيبَةَ أَتَكْتَحِلُ فِي عِدَّتِهَا مِنْ وَفَاةِ زَوْجِهَا فَقَالَتْ أَتَتِ امْرَأَةٌ إِلَى النَّبِيِّ صلى الله عليه وسلم فَسَأَلَتْهُ عَنْ ذَلِكَ فَقَالَ ‏ "‏ قَدْ كَانَتْ إِحْدَاكُنَّ فِي الْجَاهِلِيَّةِ إِذَا تُوُفِّيَ عَنْهَا زَوْجُهَا أَقَامَتْ سَنَةً ثُمَّ قَذَفَتْ خَلْفَهَا بِبَعْرَةٍ ثُمَّ خَرَجَتْ وَإِنَّمَا هِيَ أَرْبَعَةُ أَشْهُرٍ وَعَشْرًا حَتَّى يَنْقَضِيَ الأَجَلُ ‏"‏ ‏.‏

It was narrated from Zainab that a woman asked Umm Salamah and Umm Habibah whether she could put on kohl during her 'Iddah following her husband's death. She said:"A woman came to the Prophet and asked him about that, and he said: 'During the Jahiliyyah, if her husband died, one of you would stay (in mourning) for a year, then she would throw a piece of dung then come out. Rather it (the mourning period) is four months and ten days, until the term prescribed is fulfilled

Reference

Sunan an-Nasa'i 3541

In-book

Book 27, Hadith 155