The Book of Divorce
Ṣaḥīḥ Muslim 3732
قَدْ كَانَتْ إِحْدَاكُنَّ تَكُونُ فِي شَرِّ بَيْتِهَا فِي أَحْلاَسِهَا - أَوْ فِي شَرِّ أَحْلاَسِهَا فِي بَيْتِهَا - حَوْلاً فَإِذَا مَرَّ كَلْبٌ رَمَتْ بِبَعَرَةٍ فَخَرَجَتْ أَفَلاَ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا
qad kānat iḥdākunna takūnu fī sharri baytihā fī aḥlāsihā-aw fī sharri aḥlāsihā fī baytihā-ḥawlan fa-idhā marra kalbun ramat bibaʿaratin fakharajat afalā arbaʿaha ashhurin waʿashran
Transliteration generated from the Arabic vowel marks
The full narration
Zainab bint Umm Salama (Allah be pleased with her) reported on the authority of her mother that a woman lost her husband. (As her eyes were ailing) they (her kith and kin) entertained fear about her eyes, so they came to Allah's Apostle (ﷺ) and sought permission for the use of collyrium, whereupon Allah's Messenger (ﷺ) said:One among you used to spend one year in a dungeon dressed in worst clothes. (And at the end of this period) she threw dung at the dog which happened to pass that way and then she came out (of her 'Idda). Can't she (wait) even for four months and ten days?
Source
Ṣaḥīḥ Muslim · 3732