Sunan an-Nasa'i, Book 27, Hadith 152 (In-Book) ⓘ

Zainab bint Abi Salamah narrated that her mother Umm Salamah said: "A woman from the Quraish came and said: 'O Messenger of Allah, my daughter's eyes are inflamed; shall I apply kohl to her?' (The daughter's) husband had died so (the Prophet) said: 'Not until four months and ten days (have passed).' Then she said: 'I fear for her sight.' He said: 'No, not until four months and ten days (have passed). During the Jahiliyyah one of you would mourn for her husband for a year, then when one year had passed she would throw a piece of dung.'"

أَخْبَرَنَا الرَّبِيعُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا شُعَيْبُ بْنُ اللَّيْثِ، عَنْ أَبِيهِ، قَالَ حَدَّثَنَا أَيُّوبُ، - وَهُوَ ابْنُ مُوسَى - قَالَ حُمَيْدٌ وَحَدَّثَتْنِي زَيْنَبُ بِنْتُ أَبِي سَلَمَةَ، عَنْ أُمِّهَا أُمِّ سَلَمَةَ، قَالَتْ جَاءَتِ امْرَأَةٌ مِنْ قُرَيْشٍ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنَّ ابْنَتِي رَمِدَتْ أَفَأَكْحُلُهَا ‏.‏ وَكَانَتْ مُتَوَفًّى عَنْهَا ‏.‏ فَقَالَ ‏"‏ أَلاَ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا ‏"‏ ‏.‏ ثُمَّ قَالَتْ إِنِّي أَخَافُ عَلَى بَصَرِهَا فَقَالَ ‏"‏ لاَ إِلاَّ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا قَدْ كَانَتْ إِحْدَاكُنَّ فِي الْجَاهِلِيَّةِ تَحِدُّ عَلَى زَوْجِهَا سَنَةً ثُمَّ تَرْمِي عَلَى رَأْسِ السَّنَةِ بِالْبَعْرَةِ ‏"‏ ‏.‏