It's wedding season again, and couples all over the U.S. will recite that inane quote from Ruth 1:16-17:
And Ruth said, Entreat me not to leave thee, or to return from following after thee: for wither thou goest, I will go; and where thou lodgest, I will lodge: thy people shall be my people, and thy God my God. (17) Where thou diest, will I die, and there will I be buried: the LORD do so to me, and more also, if aught but death part thee and me.
Ruth said this to her mother-in-law, another woman, not to her husband. After the death of both women's husbands, Ruth declares her intention to stay with her mother-in-law, Naomi, rather than be left behind when Naomi remarries. What other choice did Ruth have? Prostitution? Panhandling? In the end Ruth marries one of Naomi's relatives, has kids, and YIPPEE! God's plan is restored.
Family loyalty is supposedly mandated by the Commandment "Thou Shalt Obey they Mother and Father." There is no corollary commandment to parents to care for their children. Perhaps the Old Guy in the Sky assumed that even the most evil of parents would do this without being commanded to do it. The "moral" of this story is that once you've been given away to your husband's family, you belong to them forever. If you're going to use this at a wedding, it should probably be said by the bride while facing her future husband's family. It has nothing to do with a promise to him.
This of course derives from the comandment to honor thy father & mother. Naomi has become Ruth's mother by virtue of marriage. She gets married off to someone else in the family, which may have been due more to pity or obligation than to any love-matching. Again, nothing to do with modern marriage practices.
Ruth wasn't expressing loyalty or even love. She was expressing her obedience to an archaic notion that women are possessions. She was essential declaring that she was indeed Naomi's baggage and putting a tag on herself.