Musnad Abu Ya'la al-Mawsili 6:29

Zuhayr narrated to us, Makki ibn Ibrahim narrated to us, Hashim ibn Hashim narrated to us, from Amir ibn Sa’d ibn Abi Waqqas, from Sa’d, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever consumes seven Ajwa dates in the morning, neither poison nor magic will harm him that day." Hashim said: "I do not know that Amir mentioned it except as the Ajwa of Al-Aliyah."