Hadith 5:91
Ibn al-Mubarak narrated to us, from Hizam (Haram) ibn Hakim, from his father, from his grandfather, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "In every forty pasturing camels, there is a *bint labun* (a two-year-old female camel). Camels shall not be separated from their calculation. Whoever gives it seeking reward, then for him is his reward. It is one of the decrees of our Lord. It is not lawful for the family of Muhammad to have anything from it."
حدثنا بن مبارك عن حزام ( ( ( حرام ) ) ) بن حكيم عن أبيه عن جده قال سمعت رسول الله صلى الله عليه وسلم يقول في كل إبل سائمة أربعين بنت لبون لا يفرق إبل عن حسابها من أعطاها مؤتجرا فله أجره عزمة من عزمات ربنا لا يحل لآل محمد منها شيء