Sahih Bukhari, Chapter: Funerals (Al-Janaaiz)

When the news of the death of Abu Sufyan reached from Sham, Um Habiba on the third day, asked for a yellow perfume and scented her cheeks and forearms and said, "No doubt, I would not have been in need of this, had I not heard the Prophet saying: "It is not legal for a woman who believes in Allah and the Last Day to mourn for more than three days for any dead person except her husband, for whom she should mourn for four months and ten days."