Did Ibn Umar, may Allah be pleased with him, divorce his wife while she was menstruating, and what is the ruling on someone who divorced his wife and then took her back the next day due to his ignorance of the waiting period (iddah)?

Abdullah ibn 'Umar divorced his wife while she was menstruating. The Prophet, peace and blessings be upon him, ordered him to take her back immediately, then leave her until she became pure, then menstruate a second time, then become pure. If he wished, he could then keep her after this purity, or divorce her before he had intercourse with her. Therefore, it is obligatory for anyone who divorces his wife while she is menstruating to take her back immediately.