Sahih Muslim
The Book of Transactions (Kitab Al-Buyu)
Book Number: 010 / Hadith Number: 3634
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (may peace be'upon him) as saying: He who bought a goat having its udder tied up should go back with it, milk it, and, if he is satisfied with its milk, he should retair it, otherwise he should return it along with a sa' of dates.