Sahih al-Bukhari 5446
Narrated Jabala bin Suhaim.:
At the time of Ibn Az-Zubair, we were struck with famine, and he provided us with dates for our food. 
`Abdullah bin `Umar used to pass by us while we were eating, and say, "Do not eat two dates together 
at a time, for the Prophet (ﷺ) forbade the taking of two dates together at a time (in a gathering)." Ibn 
`Umar used to add, "Unless one takes the permission of one's companions."
حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا جَبَلَةُ بْنُ سُحَيْمٍ، قَالَ أَصَابَنَا عَامُ سَنَةٍ مَعَ ابْنِ الزُّبَيْرِ فَرَزَقَنَا تَمْرًا، فَكَانَ عَبْدُ اللَّهِ بْنُ عُمَرَ يَمُرُّ بِنَا وَنَحْنُ نَأْكُلُ وَيَقُولُ لاَ تُقَارِنُوا فَإِنَّ النَّبِيَّ صلى الله عليه وسلم نَهَى عَنِ الْقِرَانِ‏.‏ ثُمَّ يَقُولُ إِلاَّ أَنْ يَسْتَأْذِنَ الرَّجُلُ أَخَاهُ‏.‏ قَالَ شُعْبَةُ الإِذْنُ مِنْ قَوْلِ ابْنِ عُمَرَ‏.‏