It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) forbade the transaction of exchanging two animals for one on credit, but if the transaction is done in cash, then there is no harm in it.

Abdullah says that I said to my father, Imam Ahmad: I heard Abu Khaythamah saying that the narrator Nasr bin Bab is a liar. Upon this, he said "Astaghfirullah" and began to express astonishment, saying "a liar?" The only reason the hadith scholars have criticized him is that he narrated hadith from Ibrahim al-Saigh, and Ibrahim al-Saigh is from the people of his city, so hearing (hadith) from him is not something surprising.