Sahih al-Bukhari, Hadith 2489 ⓘ
Narrated Ibn `Umar: The Prophet decreed that one should not eat two dates together at a time unless he gets the permission from his companions (sharing the meal with him).
حَدَّثَنَا خَلاَّدُ بْنُ يَحْيَى، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا جَبَلَةُ بْنُ سُحَيْمٍ، قَالَ سَمِعْتُ ابْنَ عُمَرَ ـ رضى الله عنهما ـ يَقُولُ نَهَى النَّبِيُّ صلى الله عليه وسلم أَنْ يَقْرُنَ الرَّجُلُ بَيْنَ التَّمْرَتَيْنِ جَمِيعًا، حَتَّى يَسْتَأْذِنَ أَصْحَابَهُ.
also referenced under: Book 47, Hadith 7 (In-Book) & Volume 3, Book 44, Hadith 669 (USC-MSA)