The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqa'iq)
Muslim :: Book 42 : Hadith 7073
Sa'd b. Abu Waqqas is reported to have, said: By Allah, I am the first person amongst the Arabs to throw an arrow in the cause of Allah and we used to go with Allah's Messenger (may peace be upon him) and there was no food for us to eat but only the leaves of hubla and samur trees (they are wild trees) and as a result thereof one amongst us would relieve himself as does the goat. (How strange it is) that now the people of Banu Asad (the progeny of Zubair) instruct me in religion and try to impose punishment upon me (in regard to it). If it is so (that I am so ignorant of religion), then indeed, I am undone and my deeds have been lost. Ibn Numair, however, did not make a mention of the word (idhan) thus? (in his narration).