Wages (Kitab Al-Ijarah)
Dawud :: Book 23 : Hadith 3409
Narrated Ubaydah ibn as-Samit:
I taught some persons of the people of Suffah writing and the Qur'an. A man of them presented to me a bow. I said: It cannot be reckoned property; may I shoot with it in Allah's path? I must come to the Apostle of of Allah (peace_be_upon_him) and ask him (about it). So I came to him and said : Apostle of Allah (peace_be_upon_him), one of those whom I have been teaching writing and the Qur'an has presented me a bow, and as it cannot be reckoned property, may I shoot with it in Allah's path? He said: If you want to have a necklace of fire on you, accept it.