What does Ruth 1:15 mean?

Two women are on their way to Bethlehem, of the three who initially set out from Moab. Naomi moved out of Israel with her husband and sons ten years prior because of a famine. Since then, her husband and sons died, and she is left with two Moabite daughters-in-law. She sees no way the women can remain together without living in poverty. Naomi has convinced her daughter-in-law Orpah to return to her family and seek another husband. Ruth, however, is more resolved (Ruth 1:1–14).

Here, Naomi continues to try to convince Ruth to return to Moab. She uses peer pressure, noting Orpah's departure. Yet Ruth clearly understands the implications of her choice. This includes personal, cultural, and religious consequences.

The Moabites worship Chemosh (Numbers 21:29). Not much about this idol is known except that the Israelites often betray God to worship it (1 Kings 11:7). Solomon's worship of Chemosh is one of the reasons God split the nation (1 Kings 11:31–33). During the time of Jehoshaphat, one of Judah's better rulers, the king of Moab thought their loss to the Israelites was because Chemosh was angry with them. To try to appease his god, Mesha sacrificed his son (2 Kings 3). Chemosh didn't react, of course (1 Corinthians 8:4), and the plan was foiled (2 Kings 3:22–27).

In the next verse, Ruth systematically rebuts Naomi's earlier arguments. Naomi tells her that Orpah has "gone back;" Ruth tells her, "Where you go I will go." Naomi mentions Orpah's people; Ruth says, "Your people shall be my people." Naomi warns Ruth she will have to leave her gods; Ruth replies, "Your God [shall be] my God." Naomi tells Ruth to "return after your sister-in-law," Ruth responds, "Do not urge me to…return from following you."

In fact, Ruth adds to her vow. She will not only live with Naomi, but she will also be buried with Naomi. And if she breaks this promise, she calls on God to strike her down (Ruth 1:17).