Do you know 'Abdullah b. Umar? He said: Yes. He said: It was he who divorced his wife jn the state of menses and 'Umar went to Allah's Apostle (ﷺ) and gave him this information. and he commanded him that he should take her back; and he (Abu Tawus) said: I did not hear any addition to this (hadith) from my father.
Sahih Muslim Book 18, Hadith 18
← Previous Hadith This hadith has been narrated on the authority of Shu'ba with the same chain of transmitters but with a slight variation in wording.

Sahih Muslim Book 18, Hadith 17 Next Hadith → What is your opinion about the person who divorced his wife in the state of menses? Thereupon he said: Ibn Umar (Allah be pleased with them) divorced his wife during the lifetime of Allah's Messenger (ﷺ) while she was in the state of menses. Upon this Allah's Messenger (ﷺ) told him to take her back and so he took her back and he (further) said: When she is pure, then either divorce her or retain her. Ibn 'Umar (Allah be pleased with them) said that Allah's Apostle (ﷺ) then recited this verse:" O Apostle, when you divorce women, divorce them at the commencement of their prescribed period" (Ixv 1).

Sahih Muslim Book 18, Hadith 19