Musnad Ahmad 33:217

Nasr ibn Bab narrated to us, from Hajjaj, from Abu al-Zubayr, from Jabir ibn Abdullah al-Ansari, that he said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade the selling of an animal for an animal on credit: two for one, but there is no harm in it hand-to-hand." Abdullah narrated to us: I said to my father: "Did you hear Abu Khaythama say: 'Nasr ibn Bab is a liar'?" He said: "I seek forgiveness from Allah, a liar? They only criticized him because he narrated from Ibrahim al-Sa'igh, and Ibrahim al-Sa'igh is from the people of his town, so it is not denied that he heard from him."