At the time of Ibn Az-Zubair, we were struck with famine, and he provided us with dates for our food. ʿAbdullah bin ʿUmar 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 ʿUmar used to add, "Unless one takes the permission of one's companions." (Using translation from Bukhārī 5446)   

أَصَابَنَا عَامُ سَنَةٍ مَعَ ابْنِ الزُّبَيْرِ فَرُزِقْنَا تَمْرًا فَكَانَ عَبْدُ اللهِ بْنُ عُمَرَ يَمُرُّ بِنَا وَنَحْنُ نَأْكُلُهُ فَيَقُولُ لَا تُقَارِنُوا فَإِنَّ رَسُولَ اللهِ ﷺ نَهَى عَنِ الْإِقْرَانِ ثُمَّ قَالَ إِلَّا أَنْ يَسْتَأْذِنَ الرَّجُلُ أَخَاهُ قَالَ شُعْبَةُ الْإِذْنُ مِنْ قَوْلِ ابْنِ عُمَرَ