There is more to this simple "country romance" than meets the eye.  Ruth was the great-grandmother of King David.  By putting Ruth in the royal lineage of David, the Bible is "contaminating" his bloodline. What has happened to the holy nation, when even its greatest leader is of mixed blood?

         

What happened is that a formerly minor theme of Scripture, an exceptional note, has burst into the foreground  -- the idea that the Gentiles can be included in the work of God on earth, that they can belong to His kingdom of priests.  This "innovation" did not by any means nullify the elevation of Israel above other nations and peoples, nor erase lines of distinction laid down in the Pentateuch,  but it declared an "open door" (or at least a door that was ajar) whereby Godfearing outsiders could leave the land of their forefathers and join themselves to the Covenant people, becoming heirs with them of the blessings of God.  

         

The story of Ruth is in itself rather trite and commonplace --  remarriage of a widow, big deal.  It must have happened repeatedly in Israel, so long as both parties were Israelites.  What gives it punch is the sole fact of Ruth's nationality.  In this, it is like Jesus' parable of the Good Samaritan (Lk 10:25-37).  The stories draw power not from the events themselves, but from the crossing of categories, the inclusion of "immoral" characters behaving honorably and being accepted by God.  Thus the "point" of Ruth is not about widows or kinsman-redeemers or property laws. It is about the "ingrafting" of a Moabite into the royal lineage (to use a Pauline concept).  And this is a challenge to the entire Pentateuchal tradition.

         

An even stronger challenge is the fact that the protagonist, the person who stood up for God and risked all for Him, was Ruth.  Naomi the Israelite was a weak soul, defeated by life, an object of compassion.  Boaz was not the hero, either.  He merely approved of Ruth's conduct and responded to her faith.  It was not his idea to act as the redeemer.  His acceptance of her was symbolic of the approval of God Himself.  It was Ruth who is the hero.  She freely bound herself to Naomi and to Naomi's God, she left her homeland to accompany Naomi to a life of certain poverty and discrimination, she went out to the fields to provide for Naomi, she followed Naomi's scheme to entrap Boaz.  She is the central character whose actions form the focus of the story.  She is the woman of faith who stands in the heritage of Abraham to challenge the legacy of Moses.    
       
What she challenged was the exclusion of foreigners from God's plan in history, and their characterization as perennial enemies to the purposes of God.  Ruth bore witness that the flower of faith can take root in alien soil -- though it must then be transplanted to Israel.  Ruth's example is all the more striking when contrasted with the actions of her Israelite contemporaries in the Book of Judges.  The best of them fell into idolatry or Canaanite religious practices (Gideon, Jephthah), while the worst of them acted like Sodomites (the men of Gibeah).  By contrast, Ruth exhibited a vital faith in the God of Israel, a "pure" faith like that of Abraham, not undergirded by any teachings of the Law or by the prescribed sacrifices.

         

There is, in fact, an interpretation of Ruth that states it was written after the Babylonian Exile (581 - 537 BC), in reaction to strict rules against intermarriage imposed on the returnees by Ezra. (See the units on Ezra and Nehemiah in this study).   Since Ezra's regulations echoed those of Moses, the point is the same -- the Book of Ruth opposes the traditional prohibition of intermarriage between Israelites and surrounding nations.