An explanation of interest

The Creature From Jekyll Island (pp. 191-192):

WHO CREATES THE MONEY TO PAY THE INTEREST?

One of  the most perplexing questions associated with  this proc-
ess is "Where does  the money come  from  to pay  the  interest?"  If  you borrow $10,000 from a bank at 9%, you owe $10,900. But the bank only manufactures $10,000  for  the  loan.  It would seem,  therefore, that there is no way that you-and all others with similar loans- can possibly payoff your indebtedness. The amount of money put into circulation just isn't enough to cover the total debt, including interest. This has led some to the conclusion that it is necessary for
you to borrow the $900 for the interest, and  that, in turn, leads to still more interest. The assumption  is that, the more we borrow, the more we have  to borrow, and  that debt based on fiat money is a  never-ending spiral leading inexorably  to more and more debt.
This is a partial truth. It  is true that there is not enough money created to  include the interest, but  it  is a fallacy that  the only way  to pay  it  back  is to borrow still more. The assumption fails to take into account the exchange value of labor.  Let us assume  that you pay back your $10,000 loan at the rate of approximately $900 per month and that about $80 of that represents interest. You realize you are hard pressed  to make your payments so you decide  to  take on a part-time  job.
The bank, on  the other hand,  is now making $80 profit
each month on your loan. Since this amount is classified as "interest," it  is not extinguished as is the larger portion which is a return of  the loan  itself. So this remains as spendable money  in  the account of the bank. The decision  then is made to have  the bank's floors waxed once a week. You respond  to  the ad in the paper and are hired at $80 per month to do the job. The result is that you earn  the money to pay the interest on your loan, and-this  is the point-the
money you receive  is  the same money which you previously had paid. As long as you perform labor  for  the bank each month,  the same dollars go  into  the bank as  interest,  then out the  revolving door as your wages, and  then back  into  the bank as loan repayment.
It  is not necessary  that you work directly for the bank. No matter where you earn the money, its origin was a bank and its ultimate destination is a bank.
The loop through which it travels can be large or small, but the  fact  remains all  interest is paid eventually by human  effort. And  the significance of  that  fact is even more startling than the assumption that not enough money is created to pay back the interest. It is that the total of this human effort ultimately is for
the benefit of those who create fiat money. It is a  form of modern serfdom in which the great mass of society works as  indentured servants to a ruling class of  financial nobility.