The law he references is the law of the Year of Jubilee (Lev 25:13-17).
Once upon a time, the US dollar was tied to the value of gold (gold standard). The idea was to tie money to a fixed value. You could take your paper dollar to the bank and receive gold in exchange. Very rarely you might still come across a silver certificate in circulation, which was the same in that the value of the dollar was tied to silver. The gold standard was abandoned in 1971.
Since then, in the United States, the value of currency essentially declines each year as it relates generally to inflation. We might remember for example that a postage stamp used to cost $0.05, but today it is $0.53. The buying power of a dollar has decreased over time. It is debased. A horrid example of hyperinflation is the value of a German mark in the Weimar Republic between 1921 to 1923. People would be paid and load wheelbarrows with near worthless paper money to buy a loaf of bread.
For those under the Mosaic Law, the value of currency was tied to the land, to something that in itself had value in that it produced a crop. This is similar to the idea of tying currency to gold.
‘According to the multitude of years you shall increase its price, and according to the fewer number of years you shall diminish its price; for he sells to you according to the number of the years of the crops. verse 16
Jubilees ran for 50 years. So, if you bought a piece of land that had 20 years left of the 50 to the year of Jubilees, the price was more than if you bought land that had 10 years left. Each 50 years therefore, the value of the land was reset, rather than debased. Inflation causes prices to go up and debases the currency. The Law of Jubilees causes prices to decrease and maintains the value.