It is narrated from Sayyiduna Abdullah bin Umar, may Allah be pleased with them both, that he said: I asked the Noble Prophet, peace and blessings be upon him, whether I could buy gold in exchange for silver or silver in exchange for gold. The Prophet, peace and blessings be upon him, said: When you purchase one thing in exchange for another, your companion should not part from you while there remains anything related to that transaction between you and him.