(Canto 11, line 48)
The crimes which "Sodom and Cahors", that is, homosexuals and moneylenders, commit against God are here explained as committing crimes against the Nature that God has created and the actions and works which Nature causes people to engage in. Even accepting the medieval worldview according to which "sodomy" should be considered automatically "unnatural", it is somewhat unintuitive why the same applies to lending money at a rent. The word "bounty" provides some clues: since Nature offers such a bounty of riches for man to enjoy, which it is "natural" for him to imitate and produce what he needs from, he should not "artificially" try to create his wealth and comfort.
"Sodomites" take their name from the biblical city of Sodom, which God decided to destroy together with Gomorrah in Genesis 18-19 because of all the various sins its inhabitants engaged in. Cahors, on the other hand, is a city in France which in medieval times was viewed as a "nest" for usurers.