The Art of Gentle Rebuke: Instructing the Convert
(ח) וַיֹּאמֶר֩ בֹּ֨עַז אֶל־ר֜וּת הֲל֧וֹא שָׁמַ֣עַתְּ בִּתִּ֗י אַל־תֵּלְכִי֙ לִלְקֹט֙ בְּשָׂדֶ֣ה אַחֵ֔ר וְגַ֛ם לֹ֥א תַעֲבוּרִ֖י מִזֶּ֑ה וְכֹ֥ה תִדְבָּקִ֖ין עִם־נַעֲרֹתָֽי׃

(8) Then said Boaz unto Ruth: ‘Hearest thou not, my daughter? Go not to glean in another field, neither pass from hence, but abide here fast by my maidens.

(כא) וַתֹּ֖אמֶר ר֣וּת הַמּוֹאֲבִיָּ֑ה גַּ֣ם ׀ כִּי־אָמַ֣ר אֵלַ֗י עִם־הַנְּעָרִ֤ים אֲשֶׁר־לִי֙ תִּדְבָּקִ֔ין עַ֣ד אִם־כִּלּ֔וּ אֵ֥ת כָּל־הַקָּצִ֖יר אֲשֶׁר־לִֽי׃ (כב) וַתֹּ֥אמֶר נָעֳמִ֖י אֶל־ר֣וּת כַּלָּתָ֑הּ ט֣וֹב בִּתִּ֗י כִּ֤י תֵֽצְאִי֙ עִם־נַ֣עֲרוֹתָ֔יו וְלֹ֥א יִפְגְּעוּ־בָ֖ךְ בְּשָׂדֶ֥ה אַחֵֽר׃ (כג) וַתִּדְבַּ֞ק בְּנַעֲר֥וֹת בֹּ֙עַז֙ לְלַקֵּ֔ט עַד־כְּל֥וֹת קְצִֽיר־הַשְּׂעֹרִ֖ים וּקְצִ֣יר הַֽחִטִּ֑ים וַתֵּ֖שֶׁב אֶת־חֲמוֹתָֽהּ׃

(21) And Ruth the Moabitess said: ‘Yea, he said unto me: Thou shalt keep fast by my young men, until they have ended all my harvest.’ (22) And Naomi said unto Ruth her daughter-in-law: ‘It is good, my daughter, that thou go out with his maidens, and that thou be not met in any other field.’ (23) So she kept fast by the maidens of Boaz to glean unto the end of barley harvest and of wheat harvest; and she dwelt with her mother-in-law.

(יא) ותאמר רות המואביה גם כי אמר אלי עם הנערים אשר לי תדבקין אמר רבי חנין בר לוי: בודאי מואביה היא זו, הוא אמר וכה תדבקין עם נערותי, והיא אמרה עם הנערים אשר לי...

(11) And Ruth the Moabitess said, "Indeed, he said to me, 'You will stay close to my young men...' Rabbi Chanin ben Levi said, Certainly she was a Moabitess! For he (Boaz) said 'Stay here by my young women' and she said, 'with my young men.'

In the JPS Commentary on Ruth, Rabbi Dr.Tamara Eskenazi writes: "All three times the narrator refers to Ruth as a Moabite appear in connection with Naomi: (1:22, 2:2, 2:22) ... This may signal the extent to which Ruth's "Moabiteness" colors Naomi's relation to her."

(יח) ותחדל לדבר אליה . מכאן אמרו אין מרבין עליו ואין מדקדקין עליו :

(18) She ceased to argue with her: From here we learn that we do not overburden [the prospective convert] nor are we overly meticulous with him.

The Rabbis (Yevamot 47b) and Rashi cast Naomi as Ruth's conversion instructor.

(לה) וַתַּשְׁקֶ֜יןָ גַּ֣ם בַּלַּ֧יְלָה הַה֛וּא אֶת־אֲבִיהֶ֖ן יָ֑יִן וַתָּ֤קָם הַצְּעִירָה֙ וַתִּשְׁכַּ֣ב עִמּ֔וֹ וְלֹֽא־יָדַ֥ע בְּשִׁכְבָ֖הּ וּבְקֻמָֽהּ׃ (לו) וַֽתַּהֲרֶ֛יןָ שְׁתֵּ֥י בְנֽוֹת־ל֖וֹט מֵאֲבִיהֶֽן׃ (לז) וַתֵּ֤לֶד הַבְּכִירָה֙ בֵּ֔ן וַתִּקְרָ֥א שְׁמ֖וֹ מוֹאָ֑ב ה֥וּא אֲבִֽי־מוֹאָ֖ב עַד־הַיּֽוֹם׃
(35) And they made their father drink wine that night also. And the younger arose, and lay with him; and he knew not when she lay down, nor when she arose. (36) Thus were both the daughters of Lot with child by their father. (37) And the first-born bore a son, and called his name Moab—the same is the father of the Moabites unto this day.

Moabites were associated with sexual sins, drunkenness, and excess.

In his commentary on the Book of Ruth, Rabbi Meir Zlotowitz writes: "Or, as a Moabite, Ruth was not intimately familiar with the Hebrew differentiation between the masculine and feminine forms. ... Ruth mistakenly used the masculine form without intending to be suggestive, because, as the Midrash interprets, "She was a Moabite!"