The scene is late night on the threshing floor. Rus and Boaz are all alone. They spend the night together, with the scene ending "And she lay at his feet until morning" (Rus 3:14). Does this mean that they slept together? Is this a euphemism for marital relations?
While it might seem like a convenient and perhaps poetic way to say it, everything we know about the book argues against such an interpretation. It should, rather, be taken literally. They slept in the same room near each other.
Dr. Moshe J. Bernstein ("Two Multivalent Readings in the Ruth Narrative" in Journal for the Study of the Old Testament 50 , pp. 17-20) explains:
[T]he book of Ruth has a fourth chapter whose impact would be vitiated and whose very existence would be threatened if the third chapter ended with Boaz and Ruth consummating their relationship. The scene at the city gate would be a sham with Boaz tricking the other redeemer into relinquishing his rights to a woman who has already physically bound herself to Boaz. Considering the nobility of character shared by Ruth and Boaz, the dramatic tension would not be present, nor would the false ending in 4:4 have any force whatsoever. A careful reading of the narrative, therefore, convinces us that Ruth and Boaz cannot have been sexually intimate on the threshing floor.
More serious, however, is the textual factor which could lead us to believe that what did not happen happened. It may, in fact, be the remote cause of the non-textual factor discussed above. The vocabulary of ch. 3 contains a number of words whose usage admits of double entendre: bo ('enter'; 4, 7 twice, 14), yada ('know'; 3, 4, 14), shakhav ('lie'; 4 thrice, 7 twice, 8, 13, 14), me-raglosav ('place of his feet'; 7, 14), gilah ('reveal'; 4, 7), and kanaf ('garment'; 9). In none of these cases does the word's primary function necessitate its sexual connotation (except according to those who read va-tishkav me-raglosav in that way), but there is little doubt that the accumulation of such terminology has an effect, intended by the author, upon the reader or the listener...
Takena lone, out of the context of the chapter, these ambiguous words could point to the occurrence of sexual activity, but the configuration of the words, the sense of the sentences which they form, points in the opposite direction...
The artistic function of the conflicting connotations of words versus sentences must be to furnish, on a level beyond the literal, the sense of the sexual and emotional tension felt by the characters in the vignette. The narrative tells us straight-forwardly that no sexual intercourse has taken place on the threshing floor, that final resolutions await the scene at the city gate. All the while, however, the vocabulary of the scene indicates that it might have, that the atmosphere was sexually charged. Thus the ambivalence. The words point, beneath, the surface, to the might-have-been which the characters felt might be, while the combinations of the words emphasize the opposing reality. The author of Ruth is relying upon ambiguity of language to depict the tension of emotion, enabling him to convey the atmospherics of the scene without digressing from his narrative to describe them.