As Alter notes in his introduction to the book, the consensus of biblical scholarship is that Ruth was written as a polemic against Ezra and Nehemiah's fierce prohibitions and opposition to intermarriage with Israel's pagan neighbors, the Moabites in particular. It will be recalled that the Moabites were considered to be among the most toxic of Israel's neighbors, a most loathsome and despised people.
In light of that prejudice and the prohibitions against marrying Moabites, the polemical nature of the book of Ruth should be clear: Here's the story of a courageous and loving Moabite woman who is married by an Israelite and who becomes the great-grandmother of king David.
This much has been noted before, the tension between Ruth and Ezra-Nehemiah. But Alter goes on to make an observation about the particular style in which Ruth makes its argument. Alter observes:
It is remarkable that a story in all likelihood framed for a polemic purpose should be so beguiling. Charm is not a characteristic that one normally associates with biblical narrative, but this idyll is charming from beginning to end, understandably making it one of the most perennially popular biblical books.
As Alter continues, in "[setting] out to make Ruth the Moabite a thoroughly good person" the author of the book makes "his argument for openness to exogamy," marriages between Israelites and Moabites.
This is an utterly fascinating observation. Polemical arguments need not be raging, harsh, and cutthroat, a winner take all rhetorical combat. We can persuade through charm. We all know the saying, how we can catch more flies with honey rather than vinegar.
But it's more than just charm. The polemic of Ruth is rooted in her very good character. In the story this Moabite women is described as eshet chayil, a "worthy woman" or a "woman of valor" from Proverbs 31. In fact, Ruth, a Moabite, is the only women named in the Bible as eshet chayil.
Basically, the polemic of Ruth is an argument from character. Legally, reasoning solely from the texts of the Law, Boaz shouldn't marry Ruth. Ezra and Nehemiah have the better biblical argument. But Ruth's character, her being an eshet chayil, argues for her inclusion into the People of God.
