Hadith 1774
Zainab bint Abu Salamah (May Allah be pleased with them) said:
عن زينب بنت أبي سلمة رضي الله عنهما قالت: دخلت على أم حبيبة رضي الله عنه زوج النبي صلى الله عليه وسلم حين توفي أبوها أبو سفيان بن حرب رضي الله عنه، فدعت بطيب فيه صفرة خلوق أو غيره، فدهنت منه جارية، ثم مست بعارضيها. ثم قالت: والله مالي بالطيب من حاجة، غير أني سمعت رسول الله صلى الله عليه وسلم يقول على المنبر: "لا يحل لامرأة تؤمن بالله واليوم الآخر أن تحد على ميت فوق ثلاث ليال، إلا على زوج أربعة أشهر وعشرا" قالت زينب: ثم دخلت على زينب بنت جحش رضي الله عنها حين توفي أخوها، فدعت بطيب، فمست منه، ثم قالت: أما والله مالي بالطيب من حاجة، غير أني سمعت رسول الله صلى الله عليه وسلم يقول على المنبر: “لا يحل لامرأة تؤمن بالله واليوم الآخر أن تحد على ميت فوق ثلاث إلا على زوج أربعة أشهر وعشرًا” ((متفق عليه)).
I went to Umm Habibah (May Allah be pleased with her) the wife of the Prophet (ﷺ), when her father Abu Sufyan bin Harb (May Allah be pleased with him) died. Umm Habibah (May Allah be pleased with her) sent for a yellow coloured perfume or something else like it, and she applied it to a slave-girl and then rubbed it on her own cheeks and said: "By Allah, I have no need for perfume, I heard the Messenger of Allah (ﷺ) saying from the pulpit, 'It is not permissible for a woman who believes in Allah and the Last Day to mourn for the dead beyond three days, except for the death of her husband; in which case the period of mourning is of four months and ten days."' Zainab said: I then visited Zainab, daughter of Jahsh (May Allah be pleased with her) when her brother died; she sent for perfume and applied it and then said: "Beware! By Allah, I don't feel any need of perfume but I heard the Messenger of Allah (ﷺ) saying from the pulpit, 'It is not permissible for a woman who believes in Allah and the Last Day to mourn the dead beyond three days except in case of her husband (for whom the period is) four months and ten days."' [Al-Bukhari and Muslim]
In plain words
Two of the Prophet's wives, though grieving a father and a brother, deliberately applied perfume to show they would not mourn beyond three days, recalling his teaching. Mourning the dead is set at three days, except for a husband, where the period is four months and ten days.
Reference : Riyad as-Salihin 1774 In-book reference : Book 17, Hadith 264