Genesis 18, Three Men at Mamre

Abram, newly named Abraham, has had all the males in his family circumcised, in keeping with the new covenant with God.

Genesis 18: 1-8, Three men appear
The LORD appeared to Abraham near the great trees of Mamre while he was sitting at the entrance to his tent in the heat of the day. Abraham looked up and saw three men standing nearby. When he saw them, he hurried from the entrance of his tent to meet them and bowed low to the ground. He said, "If I have found favor in your eyes, my lord, do not pass your servant by. Let a little water be brought, and then you may all wash your feet and rest under this tree. Let me get you something to eat, so you can be refreshed and then go on your way--now that you have come to your servant." 

"Very well," they answered, "do as you say."

So Abraham hurried into the tent to Sarah. "Quick," he said, "get three seahs of fine flour and knead it and bake some bread." Then he ran to the herd and selected a choice, tender calf and gave it to a servant, who hurried to prepare it. He then brought some curds and milk and the calf that had been prepared, and set these before them. While they ate, he stood near them under a tree.

The LORD is somehow identified with the three men. 

Abraham probably follows a common custom: he quickly asks the men to come in and rest, makes humble promises about "something to eat", and then hurries to get a sumptuous banquet prepared.

I find it interesting that the location of this meeting, in an account written for people centuries later, is identified by trees.  Alter translates "great trees" as "Terebinth"; the KJV translates "great trees" as "plain".  The Hebrew word used here is a modification of elah, meaning oak or terebinth; this word will show up again in Genesis 35:4.  Apparently in these desert lands, one might identify a location by the existence of trees.

Three seahs is probably about  36 pounds or 16 kilograms, says the NIV footnotes.

Genesis 18: 9-12, Sarah laughs
"Where is your wife Sarah?" they asked him. 

"There, in the tent," he said.

Then the LORD said, "I will surely return to you about this time next year, and Sarah your wife will have a son." 

Now Sarah was listening at the entrance to the tent, which was behind him. Abraham and Sarah were already old and well advanced in years, and Sarah was past the age of childbearing. So Sarah laughed to herself as she thought, "After I am worn out and my master is old, will I now have this pleasure?"

In verse 10, the Hebrew is literally "Then he" instead of "then the LORD"; the translators assume the pronoun refers to YHWH.

Sarah has long given up on the "pleasure" of bearing a child.

Genesis 18: 13-15, Don't laugh!

Then the LORD said to Abraham, "Why did Sarah laugh and say, `Will I really have a child, now that I am old?'  Is anything too hard for the LORD? I will return to you at the appointed time next year and Sarah will have a son."

Sarah was afraid, so she lied and said, "I did not laugh." 

But he said, "Yes, you did laugh."

"The LORD" confronts Sarah and promises to return a year later.  The reporting of dialogue is delightful here.  Dialogue is somewhat rare in this book -- here we have God saying, "You laughed!", Sarah responding, like a child, "Did not!" to which God says, "Did so, did so!" Is YHWH teasing Sarah a little here?  Does she see how silly it is to deny this?  In a year she will be blessed with a young son and will get her own fill of childish behavior!

Genesis 18: 16-21, YHWH looks at Sodom

When the men got up to leave, they looked down toward Sodom, and Abraham walked along with them to see them on their way. Then the LORD said, "Shall I hide from Abraham what I am about to do? Abraham will surely become a great and powerful nation, and all nations on earth will be blessed through him. For I have chosen him, so that he will direct his children and his household after him to keep the way of the LORD by doing what is right and just, so that the LORD will bring about for Abraham what he has promised him."

Then the LORD said, "The outcry against Sodom and Gomorrah is so great and their sin so grievous that I will go down and see if what they have done is as bad as the outcry that has reached me. If not, I will know."

God decides to explain His plans to Abraham.  This is portrayed as an internal conflict of God, debating with Himself over whether to tell his friend Abraham of his plans.

One is reminded of the events just before the Great Flood; once again mankind has degenerated into evil and God plans a response.  This time it will not be a flood.

Genesis 18: 22-33, Abraham bargains with God

The men turned away and went toward Sodom, but Abraham remained standing before the LORD. Then Abraham approached him and said: "Will you sweep away the righteous with the wicked? What if there are fifty righteous people in the city? Will you really sweep it away and not spare the place for the sake of the fifty righteous people in it? Far be it from you to do such a thing--to kill the righteous with the wicked, treating the righteous and the wicked alike. Far be it from you! Will not the Judge of all the earth do right?"

The LORD said, "If I find fifty righteous people in the city of Sodom, I will spare the whole place for their sake."

Then Abraham spoke up again: "Now that I have been so bold as to speak to the Lord, though I am nothing but dust and ashes, what if the number of the righteous is five less than fifty? Will you destroy the whole city because of five people?" 

"If I find forty-five there," he said, "I will not destroy it."

Once again he spoke to him, "What if only forty are found there?" 

He said, "For the sake of forty, I will not do it."

Then he said, "May the Lord not be angry, but let me speak. What if only thirty can be found there?" 

He answered, "I will not do it if I find thirty there."

Abraham said, "Now that I have been so bold as to speak to the Lord, what if only twenty can be found there?" 

He said, "For the sake of twenty, I will not destroy it."

Then he said, "May the Lord not be angry, but let me speak just once more. What if only ten can be found there?" 

He answered, "For the sake of ten, I will not destroy it."

When the LORD had finished speaking with Abraham, he left, and Abraham returned home.

Abraham argues with God and negotiates for Sodom.  Abraham calls for "righteousness" or "justice" in God's actions.   Abraham stops his negotiotion at an agreement on ten righteous people; surely Lot and his family would account for most of the 10.

In this passage, YHWH comes across as a (very powerful) friend of Abraham, telling Abraham of his plans, promising a son, correcting Sarah's "I did not laugh." In verse 22, ancient texts and ancient Hebrew scribal traditions apparently have the phrase "but the LORD remained standing before Abraham", as if YHWH were the one waiting on Abraham, as if one might wait on a superior.  The NIV follows the Masoretic text which switches the roles, with Abraham standing before YHWH.  (Which is the original?  Did Masorete scribes change earlier texts because they were uncomfortable with "YHWH standing before Abraham"?)