It is narrated from Hazrat Fadala (may Allah be pleased with him) that once in Khaybar, a necklace was presented to the Prophet Muhammad (peace and blessings be upon him), in which gold and jewels were set. This was war booty that was being sold. The Prophet (peace and blessings be upon him) ordered that the gold attached to the necklace be separated. Then he said that gold should be sold for gold with equal weight.