It is permissible to perform 'Umrah during the months of Hajj
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ، بَشَّارٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، قَالَ سَمِعْتُ أَبَا جَمْرَةَ الضُّبَعِيَّ، قَالَ تَمَتَّعْتُ فَنَهَانِي نَاسٌ عَنْ ذَلِكَ، فَأَتَيْتُ ابْنَ عَبَّاسٍ فَسَأَلْتُهُ عَنْ ذَلِكَ، فَأَمَرَنِي بِهَا . - قَالَ - ثُمَّ انْطَلَقْتُ إِلَى الْبَيْتِ فَنِمْتُ فَأَتَانِي آتٍ فِي مَنَامِي فَقَالَ عُمْرَةٌ مُتَقَبَّلَةٌ وَحَجٌّ مَبْرُورٌ - قَالَ - فَأَتَيْتُ ابْنَ عَبَّاسٍ فَأَخْبَرْتُهُ بِالَّذِي رَأَيْتُ فَقَالَ اللَّهُ أَكْبَرُ اللَّهُ أَكْبَرُ سُنَّةُ أَبِي الْقَاسِمِ صلى الله عليه وسلم .
Abu Jam at al-Dubu'i reported: I performed Tamattu' but the people dis- couraged me to do so. I came to Ibn 'Abbas and asked him about it. He ordered me to do so. I came to the House (Ka'ba) and slept. I saw a visitant in the dream who said: 'Umra is acceptable and so is the Hajj performed for God's sake. I came to Ibn Abbas and informed him about that Which I saw in the dream whereupon he said: Allah is the Greatest, Allah is the Greatest This is the Sunnah of Abu'l-Qasim (the Holy Pro- phet) (ﷺ).