The Moral Dilemma of Debt

When we do not repay the things that we have borrowed, our payment becomes that of being reborn as a horse or ox. The story of hiro mushime is a perfect illustration of the impulse to throw the accusation back at the accuser. Even carmic justice can thus be reduced to the language of a business deal. What does it mean when we reduce moral obligations to debts?What changes when the one turns into the other?