Mujahid (may Allah have mercy on him) says that Urwah bin Zubair asked Sayyiduna Ibn Umar (may Allah be pleased with them both): "In which month did the Prophet (peace be upon him) perform Umrah?" He replied: "In the month of Rajab." When this reached Sayyidah Aisha (may Allah be pleased with her), she said: "May Allah have mercy on Abu Abdur Rahman. The Prophet (peace be upon him) performed all his Umrahs while he was present, and the Prophet (peace be upon him) did not perform Umrah in any month except Dhu al-Hijjah."