Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says that people used to consider performing Umrah during the months of Hajj as the greatest sin on the face of the earth. Therefore, they would alter the months, declaring Muharram as Safar, and they used to say: When the wounds on the camels caused by travel heal, the traces of caravans on the roads disappear, and the month of Safar passes, then it will be permissible for those performing Umrah to do so. When the Prophet Muhammad (peace and blessings be upon him) and his companions arrived on the fourth of Dhul-Hijjah, reciting the Talbiyah for Hajj, he (peace and blessings be upon him) ordered them to change their Ihram from Hajj to Umrah and to exit Ihram after performing Umrah. But they considered this a very great matter and said: O Messenger of Allah! What kind of exiting from Ihram? He (peace and blessings be upon him) said: Complete exiting from Ihram.