It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) forbade eating two dates together without the permission of one's companions.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5246
Hadith Gradingحکم دارالسلام:إسناده صحيح ، خ : 2489 ، م : 2045 .