Musnad Abu Ya'la al-Mawsili 154:171

Suwayd narrated to us, from Malik, from Nafi’, from Ibn ‘Umar, that he said: We were in the time of the Prophet (may Allah bless him and grant him peace) buying food, and he would send to us someone who would order us to move it from the place where we bought it to another place before we sold it.