Is it considered a good thing that Lot's daughters slept with their father?

Question

In Bereishis 19:30-38 the story is told how the 2 daughters of Lot thought (for whatever reason) that they should sleep with their father. From the psukim themselves, it is unclear whether or not what they did is a positive thing. Are there sources that make it clear how to relate to what they did?

Answer 1

There is a certain amount of ambiguity here.

On the one hand, we see that our Sages praise the daughters of Lot, and especially the elder daughter who took the initiative.

Nazir 23a:

אלא משל ללוט ושתי בנותיו עמו הן שנתכוונו לשם מצוה וצדיקים ילכו בם הוא שנתכוין לשם עבירה ופושעים יכשלו בם

Rather, it is comparable to Lot and his two daughters, who were with him. They, who intended to engage in sexual intercourse with him for the sake of a mitzva, as they thought that the entire world was destroyed and wished to preserve the human race, are described in the first part of the verse: “And the just walk in them.” He who intended to act for the sake of a transgression is described by the last part: “But transgressors stumble over them.”

(Translation and elucidation courtesy of sefaria.org)

Nazir 23b:

א"ר חייא בר אבין א"ר יהושע בן קרחה לעולם יקדים אדם לדבר מצוה שבשכר לילה אחת שקדמתה בכירה לצעירה זכתה וקדמה ארבעה דורות בישראל למלכו':‏

Rabbi Ḥiyya bar Avin said that Rabbi Yehoshua ben Korḥa said: A person should always come first with regard to a matter of a mitzva, as in reward of the one night that the elder daughter of Lot preceded the younger for the sake of a mitzva, she merited to precede the younger daughter by four generations to the monarchy of the Jewish people. The descendants of Ruth the Moabite ruled over the Jewish people for four generations: Obed, Yishai, David, and Solomon, before the reign of Solomon’s son Rehoboam, whose mother was Naamah the Ammonite.

(Translation and elucidation courtesy of sefaria.org)

On the other hand, our Sages castigate them for their lack of shame, especially the elder who was more brazen.

Bamidbar Rabbah 20:

וַיְהִי מִמָּחֳרָת וַתֹּאמֶר הַבְּכִירָה אֶל הַצְּעִירָה הֵן שָׁכַבְתִּי אֱמֶשׁ, לִמְּדַתָּה אֲחוֹתָהּ, וּלְפִיכָךְ חָסַךְ הַכָּתוּב עַל הַצְּעִירָה וְלֹא פֵּרְשָׁהּ, אֶלָּא (בראשית יט, לה): וַתִּשְׁכַּב עִמּוֹ, וּבַגְּדוֹלָה כְּתִיב (בראשית יט, לג): וַתִּשְׁכַּב אֶת אָבִיהָ.‏

"And it was the next day and the elder said to the younger, behold last night I slept etc." She taught her sister, therefore the verse took pity on the younger daughter and was not explicit, rather writing, "And she slept with him", as opposed to the older daughter, where it writes, "And she slept with her father."

Nazir 23b:

א"ר חייא בר אבא א"ר יוחנן מנין שאין הקב"ה מקפח אפי' שכר שיחה נאה דאילו בכירה דקריתיה מואב א"ל רחמנא (דברים ב, ט) אל תצר את מואב ואל תתגר בם מלחמה מלחמה הוא דלא אבל צעורי צערינן ואילו צעירה דקריתיה בן עמי אמר ליה (דברים ב, יט) אל תצורם ואל תתגר בם אפילו צעורי לא תצערינן כלל

Rabbi Ḥiyya bar Abba said that Rabbi Yoḥanan said: From where is it derived that the Holy One, Blessed be He, does not deprive one of even the reward for proper speech, i.e., for speaking in a refined manner? As while there is the case of Lot’s elder daughter, who called her son Moab [mo’av], which alludes to his shameful origins, as me’av means: From father, and the Merciful One says to Moses: “Do not besiege Moab, nor contend with them in war” (Deuteronomy 2:9), which indicates: It is war that is not permitted; however, with regard to harassing, the Jews were permitted to harass them. And while there is the case of Lot’s younger daughter, who called her son Ben-Ami, son of my people, without explicitly mentioning her father. With regard to her descendants, God said to Moses: “Do not harass them, nor contend with them” (Deuteronomy 2:19), which means even as far as harassing is concerned, you may not harass them at all.

(Translation and elucidation courtesy of sefaria.org)

Answer 2

There was an element of good in the naming as brought out in this story of Rav Moshe Feinstein zatzal.

I have edited the story which appears in full at the link. The original is in Igros Moshe vol. 8, introduction p15.

In November 1921, when Rabbi Moshe Feinstein was the chief rabbi of the town Luban, a Torah scholar fell seriously ill: his tongue swelled up enormously. He was on his deathbed from this illness.

Rav Moshe went to visit him. The man sent everyone else out.

The week before, which was Vayeira, the man had given a sermon in which he berated the daughters of Lot for what they had done. He criticized the brazenness of the older one in naming the child after the deed ["Moab" = "from Father"] and thereby publicizing it to everyone.

He told Rav Moshe that the night before, the daughters of Lot came to him in a dream. They rebuked him. He should have considered that everything they did had a purpose.

They thought they were the last people on earth to survive the destruction and they had to ensure the continuity of mankind. That required them committing such an act; they had no other choice.

Nevertheless when they realized that it was only the population of the five towns on the Dead Sea that had been wiped out, they felt that they had to publicize what they had done. They feared that if they did not, future generations might make a deity out of any child born to them, for they would consider it a virgin birth!

To avoid people thinking it to be a virgin birth and possibly making a religion out of the mother and daughter, they decided that they had to publicize what they did, no matter how shameful - in order to ensure that everyone understood that there is no such thing as birth without a father. So the older daughter named the first baby Moab - "from Father."

Lastly, they said to him, that is why you have to be punished [through your tongue] measure for measure, for the harsh words you spoke about us.

He concluded telling the story to Rav Moshe, turned to the wall, and passed away.

Answer 3

NAZIR 23a:

אלא משל ללוט ושתי בנותיו עמו הן שנתכוונו לשם מצוה וצדיקים ילכו בם הוא שנתכוין לשם עבירה ופושעים יכשלו בם

We speak [in the verse] of one path, whereas here [in the example given] there are two paths. Rather is it illustrated by Lot when his two daughters were with him. To these [the daughters], whose intention it was to do right, [applies], 'the just do walk in them', whereas to him [Lot] whose intention it was to commit the transgression [applies], 'but transgressors do stumble therein'.

Answer 4

Ralbag in his commentary to this incident writes as follows:

התועלת הכ"ד הוא במדות והוא שראוי שנשפוט בעניני הפעולות האנושיות לפי הכונה בהם לא לפי ענינם בעצמם הלא תראה שבנות לוט מפני שהיתה כונתם טובה בזה הפעל המגונה נמצאו נעזרות בו מהשם יתעלה וזכו אל שיצאו מהן השתי אומות שמלאו הארץ בעת מתן תורה

The twenty-fourth lesson is in character traits. And it is that it is proper to judge human activities based on the intent rather than based on their actual essence. Do you not see that the daughters of Lot because their intent was good with this degrading act ended up being helped by God may He be exalted, and they merited that these two nations that filled the world at the time of the giving of the Torah came from them.