The concept of lending money for interest hasn’t needed many defenders since roughly the Renaissance, when usury laws fell out of fashion. Even so, some people are still innocent of economics and the time value of money. They still attack the very notion of interest. Ludwig von Mises offers a pithy defense on p. 41 of 1940’s Interventionism: An Economic Analysis:
In order to do away with interest we would have to prevent people from valuing a house, which today is habitable, more highly than a house which will not be ready for use for ten years. Interest is not peculiar to the capitalistic system only. In a socialist community too the fact will have to be considered that a loaf of bread which will not be ready for consumption for another year does not satisfy present hunger.
Objections to interest then, must clear hurdles as high as human nature, hunger, and time itself. Good luck, I say.