When the backs of their camels would become all right and traces (if the pilgrims) would be effaced (from the paths) and the month of Safar would be over, then Umra would be permissible for one who wants to perform it. When Allah's Apostle ﷺ and his Companions came in the state of Ihram for performing Hajj on the fourth (of Dhu'l-Hijja) he (Allah's Apostle) commanded them to change their state of Ihram (from Hajj) to that of 'Umra. It was something inconceivable for them. So they said: Messenger of Allah, is it a complete freedom (of the obligation) of Ihram? Thereupon he said: It is a complete freedom (from Ihram).
أَنَّ الْعُمْرَةَ فِي أَشْهُرِ الْحَجِّ مِنْ أَفْجَرِ الْفُجُورِ فِي الأَرْضِ وَيَجْعَلُونَ الْمُحَرَّمَ صَفَرً وَيَقُولُونَ إِذَا بَرَأَ الدَّبَرْ وَعَفَا الأَثَرْ وَانْسَلَخَ صَفَرْ حَلَّتِ الْعُمْرَةُ لِمَنِ اعْتَمَرْ فَقَدِمَ النَّبِيُّ ﷺ وَأَصْحَابُهُ صَبِيحَةَ رَابِعَةٍ مُهِلِّينَ بِالْحَجِّ فَأَمَرَهُمْ أَنْ يَجْعَلُوهَا عُمْرَةً فَتَعَاظَمَ ذَلِكَ عِنْدَهُمْ فَقَالُوا يَا رَسُولَ اللَّهِ أَىُّ الْحِلِّ قَالَ الْحِلُّ كُلُّهُ