Riyad us Saliheen: Hadith 742

We were with 'Abdullah bin Az-Zubair (May Allah be pleased with them) in a time of famine, then we were provided with dates. (Once) when we were eating, 'Abdullah bin 'Umar (May Allah be pleased with them) passed by us and said: "Do not eat two dates together, for Messenger of Allah (ﷺ) prohibited it, unless one seeks permission from his brother (partner)."

[Al-Bukhari and Muslim].