Following the catastrophic destruction of Sodom, Lot and his two surviving daughters take refuge in an isolated cave. Overcome by a profound existential crisis and despair, the daughters devise a drastic plan to ensure the continuation of human life. The initiative is taken by the older daughter, generally understood to simply be the elder of the two [רמב״ן], though some suggest she is actually the eldest child of Lot's second wife, as his older daughters from a previous marriage perished in the city's ruin [אבן עזרא, אבי עזר, מחוקקי יהודה]. She takes the lead because her younger sister is hesitant and requires persuasion to participate in such an extreme measure [הדר זקנים].
The daughters' urgency is driven by their father's advanced age, which presents several immediate fears. Biologically, they worry he might die soon or lose his ability to father children [רש״י, ביאור שטיינזלץ]. Physically, he lacks the strength to journey to another land in search of husbands for them [ספורנו, שד״ל, מלבי״ם], or to return to his relative Abraham [קונטרס חיבה יתירה]. Furthermore, having lost all his wealth in Sodom's destruction, Lot cannot rebuild his fortune to provide them with respectable dowries [קונטרס חיבה יתירה]. The older sister also recognizes that due to his age and lack of natural desire, their father will never consciously consent to their plan. They realize they must use wine to cloud his judgment, offering it under the guise of restoring his physical strength [העמק דבר, אלשיך].
Their desperation is compounded by the belief that there are no men available to marry them. The primary approach among commentators is that the daughters genuinely believe the entire world has been consumed by fire, akin to the generation of the Flood. As naive young women who have never left the insular society of Sodom, and seeing no travelers in the aftermath, they assume they and their father are the sole survivors on earth [רשב״ם, רש״י, בכור שור, ביאור יש״ר, צאינה וראינה]. Even if they are aware that Abraham and Ishmael survived, they consider Ishmael completely unfit to father a new humanity [שפתי כהן]. Consequently, they view themselves as a new Adam and Eve, bearing the supreme responsibility to save the human race from absolute extinction [ביאור שטיינזלץ, רש״ר הירש].
Conversely, other commentators argue that the daughters know the world is still intact, having witnessed the survival of the nearby city of Zoar. Instead, their lament refers specifically to their immediate surroundings [רד״ק, שד״ל]. This localized shortage of suitors stems from a severe social stigma; they believe no one will willingly marry refugees from a cursed city [רד״ק בשם יוסף קרא, פענח רזא]. Alternatively, viewing themselves as women of distinguished lineage, they find no local men worthy of their status [הדר זקנים, דעת זקנים], or they are limited by Lot's own choice to remain isolated in the cave, refusing any contact with the local inhabitants [שד״ל].
Despite the shocking nature of their plan, the daughters express a desire for permanent, respectable unions in the manner of the rest of the world. They understand that while men might be willing to exploit them, no one will officially and honorably take them as wives [ספורנו, פענח רזא, קונטרס חיבה יתירה]. The overwhelming consensus among commentators is that the daughters' intentions are entirely pure and directed toward serving God. They act not out of lust, but from a profound sense of modesty and a supreme mission to sustain human existence. Because their underlying motives are noble, they are ultimately rewarded by becoming the matriarchs of royal dynasties, leading to King David through Ruth the Moabite, and Rehoboam through Naamah the Ammonite [פני דוד, מלבי״ם, צאינה וראינה, שפתי כהן].
Nevertheless, the narrative serves as a stark moral warning. It cautions against making fateful, life-altering decisions based merely on assumptions and imagination. It also highlights the destructive influence of wine and teaches that a person should never despair and resort to extreme measures, but should instead continue to pray and seek God's mercy [ר׳ סעדיה גאון].