Narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) and Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) appointed a man over Khaybar, and he brought some "Janib" (a superior type of) dates to the Prophet (peace and blessings of Allah be upon him). The Messenger of Allah (peace and blessings of Allah be upon him) asked him, "Are all the dates of Khaybar like this (of such quality)?" He replied, "No, by Allah, O Messenger of Allah! We exchange one sa' of these dates for two sa' of other dates, and sometimes we exchange two sa' of these dates for three sa' of other dates." So the Messenger of Allah (peace and blessings of Allah be upon him) said, "Do not do so. Instead, sell the inferior dates for dirhams, and then buy the superior dates with those dirhams."