It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "A month consists of 29 days." People conveyed this to Sayyidah Aisha (may Allah be pleased with her), so she said: "May Allah have mercy on Abu Abdur Rahman, he has made a mistake. In fact, the Prophet (peace and blessings be upon him) had separated himself from his noble wives for a month. When 29 days had passed, the Prophet (peace and blessings be upon him) came down from his upper room. The people said: O Messenger of Allah! You have come down on the 29th day. The Prophet (peace and blessings be upon him) said: 'Sometimes a month is also of 29 days.'"