Ruth is an interesting book from a literary standpoint. It is rife with puns, foreshadowing, and double, even triple-meanings. You're reading a historical account about Naomi (ironically entitled, "Ruth," since Gods special covenant with Israel is extended to Ruth through her marriage to Naomi's son). But really, the narrative is just as much about our relationship with Christ. The last Verse of Ruth makes this clear. "Obed fathered Jesse, and Jesse fathered David." - Ruth 4:22
This note is not an irrelevant detour from the history, but is rather the book's underlying thesis: From Ruth came David, the greatest King in Israel's history. And as Matthew makes clear in the beginning of his gospel, from David came Jesus, the Messiah. God was not only faithful in small things (food for Naomi and Ruth), but he also blesses them in huge things (kinsman redeemer, Boaz, continuing the lineage of Naomi). But he doesn't stop there. His overwhelming grace to the women is demonstrated in his gift of Christ as a direct descendant of Ruth, transforming a temporary "happy ending" into an eternal one.
Similarly, Ruth gives us a clear analogy of the spiritual "courtship" between us and Christ. When you come to Him, He says, ‘Do not go to glean in another field... ‘ - (Ruth 3) ‘There is salvation in no one else’(2:8; Acts 4:12). In Him, there is amazing grace. He loves us. He looks upon us favourably. He takes notice of us. He died for us (2:10; Romans 5:8). When we follow him, (1:16-17; John 6:67-69) he produces new life within us (Ruth 4:13): "Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come." - 2 cor 5:17
And our cry of joy mirrors that of the women's who exclaimed to Naomi: "He shall be to you a restorer of life and a nourisher of your old age..."-Ruth 4:17