Musannaf Ibn Abi Shayba 16:262

Abu Bakr narrated to us, he said: Ibn Fudayl narrated to us, from al-Shaybani, from Jabalah ibn Suhaym, from Ibn Umar, who said: The Messenger of Allah (may Allah bless him and grant him peace) forbade *al-iqran* (eating two dates together at once), unless you ask permission from your companions.