صحيح البخاري
Sahih Bukhari
كتاب البيوع
The Book of Sales (Bargains)
باب هل يبيع حاضر لباد بغير أجر وهل يعينه أو ينصحه:
(68) Chapter. Is it permissible for a person from the town to sell the goods of a desert dweller without taking commission? Should he he help him or try to advise him?