What command did the Prophet Muhammad (saw) give Ibn 'Umar with regards to divorcing his wife during her menses?
 Narrated Nafi`:                     Ibn `Umar bin Al-Khattab divorced his wife during her menses. Allah's Apostle 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 has ordered me so."