Chapter 44: The Book of Financial Transactions
It was narrated from Abu Hurairah that the Prophet said: "Do not go out to meet the riders, and do not bind the udders of camels and seep. Whoever has boughty anything in that manner has two choices: If he whishes he may keep it, or if he wants to return it he may return it, along with a Sa of dates." (Sahih )
Sunan an-Nasa'i 4487