I was truly amazed to learn that the first seventy-one pesukim of parshas Vayairah are stuma -closed, i.e. it is one long paragraph. Whenever a new idea is being presented in the Torah, it is awarded its own individual format. Here, what appears, on the surface, to be two separate narratives, the angles coming to Avraham and the destruction of Sedom, are clearly joined and meant for us to take notice of as a unit. The opening words of the parsha, namely "vayera eilav Hashem", have puzzled the commentaries, including the Ohr HaChaim HaKadosh, as the Torah is most vague as to what the nature of this "appearance" is. The Gemarah (Sotah 14a) teaches that we are to understand these introductory words as a mandate to engage in bikur cholim, visiting the sick; just as Hashem visited Avraham, so too are we to emulate His noble ways and visit the sick.
I'd like to suggest that the opening words convey that Hashem communicated to Avraham as the story unfolds itself. While initially Avraham is unaware that the three men are indeed angels, the vayera eilav becomes clear when the angel informs Sarah that she will have a child and the second angel heals Avraham.
I'd like to further suggest that the Torah informs us that Hashem continues the vayera / communication to include the impending destruction of Sodom and its surrounding cities. We are taught in Tana D'bei Eliyahu that we are to examine and study carefully the exemplary behavior of our avos in order that we should model and perpetuate their behavior. Avraham Avinu personifies the midah of chessed. Indeed, the Navi declares, "teetein emes l'Ya'akov v'chesed l'Avraham." Sodom personifies the antithesis of Avraham; the law of the land in Sodom was that no chessed was allowed. Any yet Avraham did not merely casually pray for Sodom, rather the Torah devotes no less than ten pesukim specifying in exact detail the prayer of Avraham on their behalf. Rav Yaakov Kaminetsky, zt"l (in Emes l'Yaakov) adjures us to note how strong and passionate the chessed of Avraham was, that he puts in so much effort and concern on their behalf.
The immediate lesson that we learn therefrom is that now that Avraham and Sarah were promised a child, Hashem is urging them to expand their horizon and show concern and responsibility for those beyond their immediate circle. We, too, are to follow in the illustrious ways of Avraham and personify that which the Gemarah (Yuma 86a) teaches that "v'ahavtah es Hashem Elokechah" is to be understood not only to require one's personal love towards Hashem, but also to conduct oneself in a manner which results in G-d becoming beloved to others. Our honesty and integrity in the workforce both with Jews and non-Jews is an additional implementation of vayera eilav Hashem.
The concept of pesuchos and stumos - breaks in the text that establish new paragraphs - is, according to many, a halachah l'Moshe miSinai. As such, the incident of Lot and his daughters in the cave which appears at the end of the seventy-one pesukim might well be the culmination of vayera eilav Hashem. How so? There is a fascinating Medrash Tanchuma Vayera (6) which states that in the merit of the mitzvah of circumcision that Avraham performed, Hashem granted him an abundance of prophecy. The Ail Todah (commenting on the Medrash Tanchuma) says that the abundance of prophecy referred to is Hashem showing Avraham the course of Jewish history. The prophecy which began with vayera ailav takes us all the way through the incident of Lot and his daughters in the cave, which led to the birth of Mashiach, the culmination of Jewish history.
I'd like to share a fascinating story which is found in the introduction to the eight volume of Igros Moshe of the late Rav Moshe Feinstein zt"l which, aside from being astonishingly insightful, will help provide an answer as to how the Mashiach can emerge from an incestuous relationship between a father and daughter. This story occurred ninety-nine years ago when Rav Moshe was a rabbi in Russia. A gentleman was sick with an unusual illness that affected his tongue which was swollen and diseased. Rav Moshe went to visit him at which time he asked that all should leave the room except for the rabbi. He proceeded to tell Rav Moshe why he had this rare sickness.
He said last week was Parshas Vayera, and he spoke especially strongly, in a most negative way, against the daughter of Lot who had the audacity and chutzpah to name the child Moav, announcing to the whole world that her father was the father of her child. That night the patient had a dream: two elderly women with covered faces came and announced that they were Lot's daughters coming from the olam haemes to answer his immoral charge. They explained: we are taught in this week's parsha (19:29), "So it was when G-d destroyed the cities of the plain that G-d remembered Abraham, so He sent Lot from amidst the upheaval when He overturned the cities in which Lot had lived." Since their survival was miraculous, they were afraid lest people should claim that an additional miracle happened and they became pregnant from the Shechinah and perhaps this would cause a religion to emerge like Christianity, therefore to prevent such a claim, they announced without a shadow of a doubt that for a woman to become pregnant you need a father and a mother and, indeed, that is what happened in the cave.
Since unfortunately, continued the patient, he spoke badly regarding the daughters of Lot, he was punished measure for measure, as indeed were the meraglim (see Rashi Bamidbar 14:37); as they were punished with a disease which began in the mouth and tongue, so too was he. Immediately thereafter he turned to the wall and died. Rav Moshe believed the man and asked his family that this story be shared in perpetuity. Rav Moshe continued, perhaps there is a midah kineged midah, G-d rewards a measure for measure. They wanted to prevent a false Messiah from emerging, therefore they merited that the real Messiah should come from them.
The sum total of what emerges from the beginning of vayera ailav Hashem through the incident in the cave is a directive to Avraham and his descendants that the actions of man, his hachnasas orchim, his prayers, and his authentic beliefs, will bring the Mashiach.