The Book of Drinks (Kitab Al-Ashriba)
Muslim :: Book 23 : Hadith 5080
Amir b. Sa'd b. Abu Waqqas, on the authority of his father, reported Allah's Messenger (may peace be upon him) having said: He who ate seven dates (of the land situated) between these two lava plains in the morning, no poison will harm him until it is evening.