As one reads the story of Ruth and her eventual marriage with Boaz, it can be seen potentially as one example of romantic love in the bible.
In the story, Ruth will not depart from Naomi so they travel to the land of Judah together. However, they are widowed women so they do not have any means of making money and are in a vulnerable place in society. They meet into Boaz and there are hints of him being kind to Ruth and looking out for her. Naomi realizes that Boaz is their family and that he could marry Naomi which would then raise their social and economic status. Ruth understands her and Naomi’s social and economic standing and that if she marries Boaz that could change. Ruth then goes to lengths to make this happen, not necessarily out of love, but out of obligation.
Although this story seems like it may be an example of ‘eros’ love, at a closer, slightly more cynical view of the story, it can be seen that it is simply a marriage out of obligation and love for Naomi rather than romantic love between Ruth and Boaz.