Sahih Bukhari
Partnership
Volume: 003 / Book Number: 044 / Hadith Number: 670
Narrated Jabala:
"While at Medina we were struck with famine. Ibn Az-Zubair used to provide us with dates as our food. Ibn 'Umar used to pass by us and say, "Don't eat two dates together at a time as the Prophet has forbidden eating two dates together at a time (in a gathering) unless one takes the permission of one's companion brother."