Musnad Abu Ya'la al-Mawsili 6:99

Abu al-Rabi' al-Zahrani narrated to us, Shuja' ibn al-Walid narrated to us, from Hashim ibn Hashim, from 'Amir ibn Sa'd, from Sa'd, who said: 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."