Volume 7, Book 63, Number 212:
Narrated Anas bin Malik:
Allah’s Apostle took an oath that he would abstain from his wives, and at that time his leg had
been sprained (dislocated). So he stayed in the Mashruba (an attic room) of his for 29 days. Then he
came down, and they (the people) said, “O Allah’s Apostle! You took an oath to abstain from your
wives for one month.” He said, “The month is of twenty nine days.”