Montesquieu
 

XXII.16 On the help that the state can get from bankers

The pur­pose of ban­kers is to change money, and not to lend it. If the prince uses them only to change his money, as he has only major busi­ness, the sligh­test pro­fit he allows them for their remit­tan­ces beco­mes a consi­de­ra­ble mat­ter ; and if they ask him for large pro­fits, he can be sure it is a flaw of admi­nis­tra­tion. When on the contrary he uses them to advance him money, their art consists in obtai­ning big pro­fits on their money without incur­ring the accu­sa­tion of usury.