On the prohibition against joining two dates or the like together when a group eat without his companions' permission

Riyad as-Salihin (The Meadows of the Righteous)

by Imam Nawawi

105. Chapter: On the prohibition against joining two dates or the like together when a group eat without his companions' permission

742. Jabala ibn Suhaym said, "We were afflicted by a year of drought while we were with Ibn az-Zubayr and were given some dates. 'Abdullah ibn 'Umar passed by us while we were eating and said, 'Do not eat two at once. The Prophet, may Allah bless him and grant him peace, forbade eating two once. Then he said, 'unless a man asks his brother for permission.'" [Agreed upon]