Deuteronomy 23:19

Why was usury (interest) forbidden only on some but not on all Jews?

PROBLEM: In Exodus 22:25, lending money with interest was only forbidden with the poor. But, here in Deuteronomy 23:19 it is forbidden with any other Jew. This raises two problems. First, why the change? Second, why the partiality?

SOLUTION: First, the change from Exodus to Deuteronomy was necessary because of the change in circumstances. Perhaps it was because it became difficult, in the process of time, to determine who was to be considered poor. Hence, it was deemed necessary to extend the prohibition to all Hebrews. Otherwise, no poor person would ever have gotten a loan, since loans would only have been made to those who could pay interest on it.