Ibn `Umar divorced his wife while she was having her menses. `Umar asked the Prophet (ﷺ) who said, "Order him (your son) to take her back, and then divorced her before her period of the 'Iddah has elapsed." I asked Ibn `Umar, "Will that divorce (during the menses) be counted?" He replied, "If somebody behaves foolishly (will his foolishness be an excuse for his misbehavior)?"
Sahih al-Bukhari Book 68, Hadith 78
← Previous Hadith Ibn `Umar bin Al-Khattab divorced his wife during her menses. Allah's Messenger (ﷺ) ordered him to take her back till she became clean, and when she got another period while she was with him, she should wait till she became clean again and only then, if he wanted to divorce her, he could do so before having sexual relations with her. And that is the period Allah has fixed for divorcing women. Whenever `Abdullah (bin `Umar) was asked about that, he would say to the questioner, "If you divorced her thrice, she is no longer lawful for you unless she marries another man (and the other man divorces her in his turn).' Ibn `Umar further said, 'Would that you (people) only give one or two divorces, because the Prophet (ﷺ) has ordered me so."

Sahih al-Bukhari Book 68, Hadith 77 Next Hadith → Zainab bint Abu Salama told me these three narrations: Zainab said: I went to Um Habiba, the wife of the Prophet (ﷺ) when her father, Abu- Sufyan bin Herb had died. Um ,Habiba asked for a perfume which contained yellow scent (Khaluq) or some other scent, and she first perfumed one of the girls with it and then rubbed her cheeks with it and said, "By Allah, I am not in need of perfume, but I have heard Allah's Messenger (ﷺ) saying, 'It is not lawful for a lady who believes in Allah and the Last Day to mourn for a dead person for more than three days unless he is her husband for whom she should mourn for four months and ten days.'"

Sahih al-Bukhari Book 68, Hadith 79