Rabbi Soloveitchik has a little different take on the Sodom incident and the daughters of Lot, mentioned in פרשת וירא.
In terms of the people of Sodom, the Rav wrote that generally, there is always room for Teshuva. The hope is that the sinner will come to his senses and repent. However, there are instances where people can deteriorate to such a point that they become pure evil.
Such was the case with the people of Sodom. They were beyond the level where they could ever return. In cases of evil of this sort, the only solution was to destroy evil. This is what Hashem was forced to do.
In the case of Lot’s daughters, the Rav views them as righteous women. They had lived long enough in Avraham Avinu’s house to learn to care about the world. The act they did with their father was necessary in order to save mankind. As distasteful such an act was, it was done for noble reasons.
The daughters were rewarded as the mother of Moab, was the ancestor of Ruth, the mother of the Davidic and Messianic dynasty. The other daughter was the mother of Amon, who Naama descended from her. She was the mother of Rechavam, King of Yehuda, son of Shlomo.