It is not lawful for a woman who believes in Allah and the Last Day to mourn for a deceased more than three [days], but for her husband, four months and ten days
Authentic hadithعن زينب بنت أبي سلمة قالت: تُوُفِّيَ حَمِيْمٌ لأم حبيبة، فدعت بصُفْرَةٍ، فَمَسحَتْ بذراعيها، فقالت: إنما أصنع هذا؛ لأني سمعت رسول الله صلى الله عليه وسلم يقول: «لا يحل لامرأة تؤمن بالله واليوم الآخر أن تُحِدَّ على ميت فوق ثلاث، إلا على زوج: أربعة أشهر وعشرًا».
A relative of Umm Habībah died, so she asked for a yellow perfume and wiped it over her arms and said: "I do this only because I heard the Messenger of Allah (may Allah’s peace and blessings be upon him) say: It is not lawful for a woman who believes in Allah and the Last Day to mourn for a deceased more than three [days], but for her husband, four months and ten days.'"
Explanation
Umm Habībah’s father passed away, and she had heard of the prohibition to mourn beyond three days except for one's husband. She wanted to comply practically, so she asked for perfume mixed with a yellow substance with which she wiped her arms. She explained why she was applying perfume. That is because she had heard the Prophet (may Allah's peace and blessings be upon him) say: "It is not lawful for a woman who believes in Allah and the Last Day to mourn for a deceased more than three [days], but for her husband, four months and ten days."
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).