Apostle of Allah, you took an oath that you would not come to us for a month, whereupon he said: The month may also consist of twenty-nine days.
Sahih Muslim Book 13, Hadith 29
← Previous Hadith The Apostle of Allah (ﷺ) separated himself from his wives for a month. (His wives said: ) He came to us on the morning of the twenty-ninth. Upon this some, of the people said: It is the morning of twenty- ninth (according to our calculation). Upon this the Messenger of Allah (ﷺ) said: The month. may also consist of twenty-nine days. The Apostle of Allah (ﷺ) then flapped his bands thrice, twice with all the fingers of both his hand (to indicate twenty-nine) and by the third time with nine (fingers).

Sahih Muslim Book 13, Hadith 28 Next Hadith → A hadith like this has been narrated on the authority of Ibn Juraij with the same chain of transmitters.

Sahih Muslim Book 13, Hadith 30