In the heat of the day the LORD appears to Abraham by the terebinth trees of Mamre. Abraham sees three men, runs to meet them, and serves them a meal. One of them promises that Sarah will have a son. Sarah, listening at the tent door, laughs within herself, for she is old and well past the age of childbearing. The LORD asks, “Why did Sarah laugh?” and then gives the great question of this lesson: “Is anything too hard for the LORD?”
Then the LORD reveals His plan to Abraham concerning Sodom and Gomorrah, “because their sin is very grave.” Abraham draws near and intercedes: “Would You also destroy the righteous with the wicked?” He asks for fifty righteous, then forty-five, forty, thirty, twenty, and finally ten. Each time the LORD agrees. Abraham's prayer rests on God's own character: “Shall not the Judge of all the earth do right?”
Two angels come to Sodom, where Lot sits in the gate. The men of the city show how deep their wickedness has gone, and the angels urge Lot to flee. Lot lingers, and the men take hold of his hand, his wife's hand and his daughters' hands, “the LORD being merciful to him.” The LORD rains brimstone and fire on Sodom and Gomorrah, but Lot's wife looks back and becomes a pillar of salt. Jesus later warned, “Remember Lot's wife.” She left Sodom with her feet, but not with her heart.
Genesis 19:29 tells us why Lot was spared: “God remembered Abraham, and sent Lot out of the midst of the overthrow.” Lot was rescued through Abraham's intercession. Yet Lot's story ends in shame in a cave. He had moved his tent toward Sodom little by little, and it cost him almost everything. Even after this, in Genesis 20 Abraham repeats his old fear in Gerar, and God again protects Sarah. God is faithful even when we are not.
Then Genesis 21 says, “And the LORD visited Sarah as He had said.” Sarah conceives and bears Abraham a son in his old age, at the set time God had spoken. Abraham is one hundred years old. They name him Isaac, which means laughter, and Sarah says, “God has made me laugh, and all who hear will laugh with me.” The laugh of doubt has become the laugh of joy. Later Hagar and Ishmael are sent away, yet God hears the boy's voice and promises to make him a nation too.