Mishkat al-Masabih 21 Foods كتاب الأطعمة 29

وَعَن سعدٍ قَالَ: سمعتُ رسولَ الله يَقُولُ: «مَنْ تَصَبَّحَ بِسَبْعِ تَمَرَاتٍ عَجْوَةٍ لَمْ يضرَّه ذَلِك الْيَوْم سم وَلَا سحر»

Sa‘d told of hearing God’s messenger say, “He who has a morning meal of seven ‘ajwa* dates will not suffer harm that day through poison or magic.” *The name of a good quality of Medina dates. (Bukhari and Muslim.)