Aside from the discussion of the technical rules and regulations that govern the laws of ribit (forbidden interest), our Gemara brings a series of statements in the realm of mussar – of ethics – that support the concept of lending without interest. The passage in 28:8 teaches that someone who increases his wealth through charging interest, ultimately gathers it for someone who has pity on the poor. In answer to the Gemara’s query – who is considered to “have pity on the poor?” – Rav explains that it is a reference to the king, Shevor Malka.
Shevor Malka – Shapur – was the name of a number of Persian kings. Our Gemara is referring to the first king Shapur, who continued his father’s success in wars against the Roman Empire, capturing the city of Netzivim and arriving at the border of Syria. In the course of a number of attacks, he not only defeated the Roman emperor Velrinus, but he captured him and held him until his death. With regard to internal matters, he was an open-minded leader, and allowed a good deal of freedom of religion. It appears that he showed an interest in Judaism and was on good terms with the amora Shmuel.
Most of the commentaries understand Rav’s teaching simply; that this is a reference to Shevor Malka, the king of Persia. Rav Hai Gaon suggests that it was Shevor Malka’s practice to confiscate money made by way of interest and distribute it to the poor. Thus it is understood to be a reference to a Persian king rather than a Jewish one, because if it were talking about a Jewish leader, the money would turn out to be used for a mitzva purpose in the end, and ribit is perceived as unmitigated evil.
Others suggest that the comparison to Shevor Malka is not to be taken literally, and it is actually a reference to the amora Shmuel, who made a habit of taking money from interest collectors and distributing it to the poor.