It was narrated from Abu Hurairah that the Messenger of Allah said: "whoever buys a Musarraha, if he is please with it when he milks it, he may keep it, and if he is not please with it, he may return it, along with a Sa of daters"' (Sahih)
SahihSahih HadithSahih MuslimBook 44 · Hadith 40