What practices are permissible in conducting an ethical business? Can one commingle produce from various fields or dilute wine before selling it? What criteria determine what is allowed or prohibited? What tactics are deemed acceptable or forbidden in a competitive commercial environment? Different rabbis offer varying perspectives on these questions. The fifth chapter delves into the laws of interest. The Mishna initiates the discussion by delineating what is interest that is prohibited by Torah law and by rabbinic law. The Gemara elucidates the terminology used in the Torah - neshech (interest causing a loss for the borrower) and marbit (interest generating gain for the lender) - and elucidates that both terms signify the existence of two negative commandments concerning lending or borrowing money with interest that both apply in all cases.