مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1627
Musnad of Sa'eed bin Zaid bin 'Amr bin Nufail
It was narrated that ‘Amr bin Huraith said: My father told me that the Prophet (ﷺ) said: “Truffle are a kind of manna, and its water is a healing for the eyes."
Musnad Ahmad 1627Sahih] .