This one is fun because Brady discusses the interpretive problem of how Boaz marrying Ruth was not violating the prohibition in the Torah against a Moabite entering the assembly. One Jewish commentary held that Mahlon and Chilion died for marrying Moabite women against the prohibitions in the Torah. This interpretation never caught on because it immediately raised the question of why Boaz wasn't judged by God for marrying Ruth.
A more pallatable explanation besides the simple contradiction narrative was to note that Boaz was a descendent of Rahab, an Ammorite, and so he was not purely of Israelite stock to begin with. Now that may not seem too appealing to people who don't think quite so highly of ethnic or regional purity of family lines but, hey, technically it works. It also explains why Boaz wasn't considered as bad as those Israelite men who married Moabite women that Nehemiah got furious about in Nehemiah 13.