Sahih al-Bukhari 6453
صحيح البخاري#6453SahihNarrated Sa`d:I was the first man among the Arabs to throw an arrow for Allah's Cause. We used to fight in Allah's Cause while we had nothing to eat except the leaves of the Hubla and the Sumur trees (desert trees) so that we discharged excrement like that of sheep (i.e. unmixed droppings). Today the (people of the) tribe of Bani Asad teach me the laws of Islam. If so, then I am lost, and all my efforts of that hard time had gone in vain
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 81:42