The Wealth of Nations by Part 2 Chapter 4 Page 21

commonly paid for the use of money by those who can give the most undoubted security. If this legal rate should be fixed below the lowest market rate, the effects of this fixation must be nearly the same as those of a total prohibition of interest. The creditor will not lend his money for less than the use of it is worth, and the debtor must pay him for the risk which he runs by accepting the full value of that use.

If it is fixed precisely at the lowest market price, it ruins with honest people, who respect the laws of their country, the credit of all those who cannot give the very best security, and obliges them to have recourse to exorbitant usurers. In a country, such as Great Britain, where money is lent to government at three per cent and to private people upon a good security at four and four and a half, the