Yunus bin Jubair (may Allah have mercy on him) once asked Sayyiduna Ibn Umar (may Allah be pleased with them both) about a man who divorces his wife during her menstrual period. He replied, "Do you know Abdullah bin Umar (may Allah be pleased with them both)?" I said, "Yes!" He said, "He also divorced his wife during her menstrual period. Sayyiduna Umar (may Allah be pleased with him) went and informed the Prophet (peace and blessings be upon him) about this, so the Prophet (peace and blessings be upon him) said: 'Tell him to take her back, then if he still wishes to divorce her, he should do so during her period of purity.'"