What jumps out, in comparison with the Muslim world, are these links of finance, trade, and violence. Whereas Persian and Arab thinkers assumed that the market emerged as an extension of mutual aid, Christians never completely overcame the suspicion that commerce was really an extension of usury, a form of fraud only truly legitimate when directed against one’s mortal enemies. Debt was, indeed, sin—on the part of both parties to the transaction. Competition was essential to the nature of the market, but competition was (usually) nonviolent warfare.
