And the LORD appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day;
This appearance of God to Abraham seems to have had in it more of freedom and familiarity, and less of grandeur and majesty, than those we have hitherto read of, and therefore more resembles that great visit which in the fulness of time the Son of God was to make to the world. He sat in the tent-door in the heat of the day - Not so much to repose himself, as to seek an opportunity of doing good, by giving entertainment to strangers.
 And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground,
And lo three men — These three men were three spiritual heavenly beings, now assuming human shapes, that they might be visible to Abraham, and conversable with him. Some think they were all three created angels; others, that one of them was the Son of God.
He bowed himself towards the ground — Religion doth not destroy but improve good manners, and teaches us to honour all men.
 And they said unto him, Where is Sarah thy wife? And he said, Behold, in the tent.
Where is Sarah thy wife? — By naming her, they gave intimation to Abraham, that tho' they seemed strangers, yet they well knew him and his family: by enquiring after her, they shewed a kind concern for the family of one, whom they found respectful to them. And by speaking of her, she over-hearing it, they drew her to listen to what was farther to be said.
 And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.
I will certainly return unto thee — And visit thee. God will return to those that bid him welcome.
 Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also?
Sarah laughed within herself — It was not a laughter of faith, like Abraham's, Genesis 17:17, but a laughter of doubting and distrust. The great objection which Sarah could not get over was her age. I am waxed old, and past child-bearing in a course of nature, especially having been hitherto barren, and which magnifies the difficulty, My lord is old also. Observe here, That Sarah calls Abraham her lord, and the Holy Ghost takes notice of it to her honour, and recommends it to the imitation of all Christian wives, 1 Peter 3:6. Sarah obeyed Abraham calling him lord, in token of respect and subjection.
 And the LORD said, Shall I hide from Abraham that thing which I do;
Shall I hide from Abraham that thing which I do — Thus doth God in his councils express himself after the manner of men, with deliberation. The secret of the Lord is with them that fear him. Those that by faith live a life of communion with God, cannot but know more of his mind than other people. They have a better insight into what is present, and a better foresight of what is to come.
 For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him.
I know Abraham that he will command his children, and his household after him — This is a bright part of Abraham's character. He not only prayed with his family, but he taught them, as a man of knowledge; nay, he commanded them as a man in authority, and was prophet and king, as well as priest, in his own house. And he not only took care of his children, but of his household: his servants were catechized servants. Masters of families should instruct, and inspect the manners of all under their roof. And this is given as the reason why God would make known to him his purpose concerning Sodom; because he was communicative of his knowledge, and improved it for the benefit of those that were under his charge.
 I will go down now, and see whether they have done altogether according to the cry of it, which is come unto me; and if not, I will know.
I will go down now and see — Not as if there were any thing concerning which God is in doubt; but he is pleased thus to express himself after the manner of men.
 And Abraham drew near, and said, Wilt thou also destroy the righteous with the wicked?
Abraham drew near — This expression intimates, A holy concern. A holy confidence; he drew near with an assurance of faith, drew near as a prince, Job 31:37.
 And Abraham answered and said, Behold now, I have taken upon me to speak unto the Lord, which am but dust and ashes:
Behold now, I have taken upon me to speak unto the Lord, who am but dust and ashes - He speaks as one amazed at his own boldness, and the liberty God graciously allowed him, considering God's greatness, he is the Lord; and his own meanness, but dust and ashes. Whenever we draw near to God, it becomes us reverently to acknowledge the vast distance that there is between us and Him. He is the Lord of glory, we are worms of the earth.
 And he said unto him, Oh let not the Lord be angry, and I will speak: Peradventure there shall thirty be found there. And he said, I will not do it, if I find thirty there.
Oh let not the Lord be angry — The importunity which believers use in their addresses to God is such, that if they were dealing with a man like themselves, they could not but fear that he would be angry with them. But he with whom we have to do is God and not man, and he is pleased when he is wrestled with. But why then did Abraham leave off asking when he had prevailed so far as to get the place spared if there were but ten righteous in it? Either, 1. Because he owned that it deserved to perish if there were not so many: as the dresser of the vineyard, who consented that the barren tree should be cut down if one year's trial more did not make it fruitful, Luke 13:9. Or, 2. Because God restrained his spirit from asking any farther. When God hath determined the ruin of a place, he forbids it to be prayed for, Jeremiah 7:16.
 And the LORD went his way, as soon as he had left communing with Abraham: and Abraham returned unto his place.
Abraham returned into his place — To wait what the event would be; and it proved that his prayer was heard, and yet Sodom not spared, because there were not ten righteous in it.