Regarding His saying: "That is because they say, 'Trade is but like interest'"—this is what they used to practice during the Pre-Islamic Period (Jahiliyyah). When a debt owed by one of them to another reached its term, the debtor would say: "Grant me a delay, and I will increase you [the amount]." When they did that during the time of Islam, the Muslims said to them: "This is interest (riba)." They replied: "No, it is the same to us whether we add [the increase] at the beginning of the transaction or when the term arrives." Thus, Allah proved them liars, stating: "But Allah has permitted trade and has forbidden interest. So whoever has received an admonition from his Lord"—meaning: the clarification found in the Quran regarding the prohibition of interest—"and desists, then what is past is his"—that is, Allah has forgiven him for what has passed—"and his affair rests with Allah"—if He wills, He will protect him from it thereafter, and if He wills, He will not—"but whoever returns [to dealing in interest]"—by deeming interest lawful—"those are the companions of the Fire."

Muhammad said: The meaning is: Whoever deems interest lawful and says, "It is like trade," and believes that after Allah’s prohibition of it, he is a disbeliever. [Verses 276-277]