Angels tell Abraham that Sarah will have a son within one year

• G-d appeared to Abraham in the plains of Mamre.
• Abraham was sitting at the entrance of the tent when the day was hot. He saw 3 men standing beside him. Abraham ran toward them, prostrated himself to the ground and asked them not to pass by, but to drink water, bathe their feet and rest under the tree. Abraham hurried to Sarah and asked her to bake cakes, he also took a good calf and hastened youth to prepare it. And he took cream and milk and the calf that he had prepared, and he placed [them] before them, and he was standing over them under the tree, and they ate.
• And they said to him, "Where is Sarah your wife?" And he said, "Behold in the tent." And he said, "I will surely return to you at this time next year, and behold, your wife Sarah will have a son."
• Sarah had already ceased to have the way of the women, so she laughed within herself. And Sarah denied it, saying, "I did not laugh," because she was afraid. And the angel said, "No, but you laughed."

Abraham bargains with G-d to spare Sodom & Gomorrah if they have enough righteous men

• And the men arose from there, and they looked upon Sodom, and Abraham went with them to escort them. G-d told Abraham that He was considering destroying Sodom and Gomorrah because their sin has become very grave. G-d did not conceal his plan because Abraham followed the way of the Lord and commanded his entire household to keep the way of the Lord in order that the Lord bring upon Abraham that which He spoke concerning him
• Abraham asked G-d if He would destroy the righteous with the wicked and asked G-d if He would destroy the cities if they would happen to have 50 righteous men. And the Lord said, "If I find in Sodom fifty righteous men within the city, I will forgive the entire place for their sake." Abraham proceeded to ask G-d to spare the cities for just 45 righteous men, just 40, just 30, just 20, just 10. Each time G-d agreed to spare the cities. And He said, "I will not destroy for the sake of the ten." And the Lord departed when He finished speaking to Abraham, and Abraham returned to his place.

• And Abraham will become Shall I conceal this (What I am doing in Sodom) from him? He is so dear to Me as to become a great nation, and through him will be blessed all the nations of the earth.
• at this time next year It was Passover, and on the following Passover, Isaac was born (check this)
• I will surely return The angel did not announce that he [himself] would return to him, but he was speaking to him as an emissary of the Omnipresent. Similarly (above 16: 10): “And the angel said to her: I will greatly multiply [your seed]” but he [the angel] did not have the power to multiply [her children], but he spoke as an emissary of the Omnipresent.
• and behold, three men One to bring the news [of Isaac’s birth] to Sarah, and one to overturn Sodom, and one to heal Abraham, for one angel does not perform two errands (Gen. Rabbah 50:2). You should know that [this is true] because throughout the entire chapter, Scripture mentions them in the plural, e.g., (below verse 8): “and they ate” ; (ibid. verse 9): “and they said to him.” Concerning the announcement, however, it says (ibid. verse 10): “And he said: I will surely return to you.” And concerning the overturning of Sodom, it says (below 19:22): “For I will not be able to do anything” ; (ibid. verse 21): “I will not overturn” (Gen. Rabbah 50:11). And Raphael, who healed Abraham, went from there to save Lot. This is what is stated:“And it came to pass when they took them outside, that he [the angel] said, ‘Flee for your life.’” You learn that only one acted as a deliverer.
• Perhaps there are fifty righteous men ten righteous men for each city, because there were five places. — [from Targum Jonathan]
• I will descend now This teaches judges that they should not decide capital punishment cases unless they see it [i.e., they must go to the site of the crime and investigate the matter.]- [Divrei David])
• If I find in Sodom, etc., the entire plac [Sodom refers to] all the cities, but because Sodom was the metropolis and the most important of them all, Scripture ascribes [the fifty righteous men] to it.
• perhaps ten will be found there For fewer [than ten] he did not ask. He said, “In the Generation of the Flood, there were eight: Noah and his sons, and their wives, but they did not save their generation.” And for nine, together with counting [G-d] he had already asked, but did not find.

• Abraham followed the way of the Lord and commanded his entire household to keep the way of the Lord in order that the Lord bring upon Abraham that which He spoke concerning him. Abraham fulfilled his part of the covenant and G-d fulfilled His part of the covenant. This repeats in every generation. Are we fulfilling our part of the covenant today?