"Amir bin Sa"d told "Umar bin "Abdul-"Azeez, when he was the governor of Madinah, that Sa’d said:

The Messenger of Allah (ﷺ) said: “Whoever eats seven "ajwah dates from between the two lava fields of Madinah on an empty stomach in the morning nothing will harm him that day until evening comes." Fulaih said: And I think he said: "And if he eats them in the evening, nothing will harm him until morning comes." ‘Umar said: “Think, O ‘Amir, about what you are narrating from the Messenger of Allah (ﷺ).” He said: “I bear witness that I have never told lies about Sa"d and Sa"d never told lies about the Messenger of Allah (ﷺ).”