It is narrated from Hazrat Ata bin Yasar that the Messenger of Allah, peace and blessings be upon him, said: "Sell dates for dates in equal measure." A man said: O Messenger of Allah, peace and blessings be upon him! Your agent at Khaybar takes one sa’ of dates and gives two sa’ in return. The Prophet, peace and blessings be upon him, said: "Call him." He was called. The Prophet, peace and blessings be upon him, asked: Do you take one sa’ by giving two sa’ of dates? He replied: O Messenger of Allah, peace and blessings be upon him! One sa’ of good dates cannot be obtained in exchange for one sa’ of inferior dates. The Prophet, peace and blessings be upon him, said: "First sell the inferior dates for money, then buy the good dates with that."