Muwatta Imam Malik (Riwayat Ibn al-Qasim)

It is 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 be upon him) appointed a man as the governor (amir) over the region of Khaybar. He brought high-quality dates. The Messenger of Allah (peace and blessings be upon him) asked him: "Are all the dates of Khaybar like this?" He replied: "No, by Allah! We give two sa' of dates and take one sa' of this kind of dates, and we give three sa' and take two sa'." The Messenger of Allah (peace and blessings be upon him) said: "Do not do so. Sell the ordinary dates for dirhams (money), then buy the high-quality dates with the money."