Nafi’ (may Allah have mercy on him) says that a man was narrating to Ibn Umar (may Allah be pleased with him) a hadith from Abu Sa’id al-Khudri (may Allah be pleased with him) regarding the buying and selling of gold and silver. Ibn Umar (may Allah be pleased with him) took my hand and that man’s hand, and we went to Abu Sa’id (may Allah be pleased with him). He stood up to welcome Ibn Umar (may Allah be pleased with him). Ibn Umar (may Allah be pleased with him) said to him:“He has narrated to me a hadith, and according to him, you narrated this hadith to him from the Prophet (peace and blessings be upon him). Did you really hear this hadith from the Prophet (peace and blessings be upon him)?”He replied:“I saw with my own eyes and heard with my own ears the Prophet (peace and blessings be upon him) saying: ‘Sell gold for gold and silver for silver, equal for equal. Do not increase or decrease, and do not sell something absent for something present among them.’”