Abu Huraira reported God's Messenger.as saying, “Do not go out to meet riders to conduct business with them; none of you must buy in opposition to one another1, nor must you bid against one another; a townsman must not sell for a man from the desert; and do not tie up the udders of camels and sheep, for he who buys them after that has been done has two courses open to him after milking them :he may keep them if he is pleased with them, and may return them along with a sa‘ of dates if he is displeased with them.” A version by Muslim has, “If anyone buys a sheep whose udder has been tied up he has three days in which to decide whether to keep it or not; but if he returns it he must return with it a sa’ of any grain but wheat.”2 (Bukhari and Muslim.) 1. When agreement has obviously been reached, although the contract has not been confirmed, no one must step in and offer a higher price. 2. Samra’. The full pharse is hinta samra’, meaning "tawny wheat" ; then the adjective is used by itself as a word for wheat.
Hadith Referenceمشكوة المصابيح / كتاب البيوع / 2847
Hadith Gradingالألبانی:مُتَّفَقٌ عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (2150) و مسلم (1412/11) [و الرواية الثانية (1524/25) و ذکرها البغوي في مصابيح السنة (2080) ]»