It was narrated that Abu Jawza: said: "I heard him - meaning Ibn 'Abbas - ailowing exchange (of Dirhams for Dirham etc., if extra was given) and that was narrated from him. Then I heard that he has taken back this opinion. I met him in Makkah and said: 'I heard that you had taken back (your opinion): He said: 'Yes. That was just my own opinion, but Abu Sa' eed narrated from the Messenger of Allah P.B.U.H that he forbade exchange (of like items if extra is given).'''