What does Ruth 1:18 mean?

Naomi fought hard for what she feels is best for Ruth, but now accepts that she's lost the argument. After losing her husband and two sons in Moab, Naomi decided to return to Bethlehem (Ruth 1:1–6). She does not want her Moabite daughters-in-law to join her. She expects to be impoverished and humiliated in Bethlehem with no male relative to see to her needs. Her young, foreign, pagan, widowed daughters-in-law will face even more danger.

To that end, Naomi has explained very clearly why following her is a bad idea. She is too old to have more sons, and even if, by some miracle, she did, Orpah and Ruth would be foolish to wait until they were grown enough to marry. There is nothing Naomi can offer the women she loves so much (Ruth 1:7–13).

Orpah has decided to obey Naomi, return home, and seek a new husband—a perfectly wise and reasonable choice. Ruth will not. Ruth would rather abandon her home, her nation, her family, and her gods and follow Naomi to the grave. Naomi may have nothing more to offer her, but Ruth will dedicate her life to Naomi through the power of Naomi's God, Yahweh (Ruth 1:14–17).

Having lived with Ruth for years, Naomi probably knows when it's futile to try to change the woman's mind. Before long, Naomi will come to realize God didn't abandon her when He allowed her husband and sons to die. God gave her Ruth. Within a year, Ruth will find a man who is willing to redeem Naomi's husband Elimelech's property and bear a son in Elimelech's name. Naomi will have her son through Ruth. Ruth will have a good husband and everything else Naomi wishes for her (Ruth 3:11; 4:13–17).

In addition, two generations later, Israel will have a godly king in Ruth's great-grandson David (Ruth 4:21–22). And, finally, the Messiah, Jesus (Matthew 1:5–16).