Sayyida Umm Salama (may Allah be pleased with her) narrated that the Prophet Muhammad (peace and blessings be upon him) swore an oath (due to an incident) that he would not go to some of his wives for a month. Then, when twenty-nine days had passed, the Messenger of Allah (peace and blessings be upon him) went to them either in the morning or in the evening. It was said to the Messenger of Allah (peace and blessings be upon him), "You had sworn an oath that you would not come for a month?" He replied, "A month can also be of twenty-nine days."