Musnad Abu Ya'la al-Mawsili 42:396

Zuhayr narrated to us, Ibn ‘Ulayyah narrated to us, from Ayyub, from Nafi‘, who said: A man narrated this hadith to Ibn ‘Umar from Abu Sa‘id al-Khudri, narrating it from the Messenger of Allah (may Allah bless him and grant him peace). So he (Ibn ‘Umar) stood up and went to him until he entered upon Abu Sa‘id, and I was with him. He said: "This man narrated a hadith to me from you, which you narrate from the Messenger of Allah (may Allah bless him and grant him peace). Did you hear it?" He said: "My eyes saw it and my ears heard it. I heard the Messenger of Allah (may Allah bless him and grant him peace) saying: 'Do not sell gold for gold, nor silver for silver, except like for like; and do not sell anything absent for something present.'"