Genesis 18:9

The promise to Sarah. The men now enter upon the business of their visit. "Where is Sarah thy wife?" The jealousy and seclusion of later times had not yet rendered such an inquiry uncourteous. Sarah is within hearing of the conversation. "I will certainly return unto thee." This is the language of self-determination, and therefore suitable to the sovereign, not to the ambassador. "At the time of life;" literally the living time, seemingly the time of birth, when the child comes to manifest life. "Sarah thy wife shall have a son." Sarah hears this with incredulous surprise, and laughs with mingled doubt and delight. She knows that in the nature of things she is past child-bearing. "Is anything too hard for the Lord?" Sarah laughed within herself, within the tent and behind the speaker; yet to her surprise her internal feelings are known to him. She finds there is One present who rises above the sphere of nature. In her confusion and terror she denies that she laughed. But he who sees what is within, insists that she did laugh, at least in the thought of her heart. There is a beautiful simplicity in the whole scene. Sarah now doubtless received faith and strength to conceive.

Verse 16-33

The conference concerning Sodom. The human manner of the interview is carried out to the end. Abraham convoys his departing guests. The Lord then speaks, apparently debating with himself whether he shall reveal his intentions to Abraham. The reasons for doing so are assigned. First. Abraham shall surely become a nation great and mighty, and therefore has the interest of humanity in this act of retribution on Sodom. All that concerns man concerns him. Second. Blessed in him shall be all the nations of the earth. Hence, he is personally and directly concerned with all the dealings of mercy and judgment among the inhabitants of the earth. Third. "I have known him." The Lord has made himself known to him, has manifested his love to him, has renewed him after his own image; and hence this judgment upon Sodom is to be explained to him, that he may train his household to avoid the sins of this doomed city, "to keep the way of the Lord, to do justice and judgment; and all this to the further intent that the Lord may bring upon Abraham what he hath spoken of him." The awful judgments of the Lord on Sodom, as before on the antediluvian world, are a warning example to all who are spared or hear of them. And those who, notwithstanding these monuments of the divine vengeance, will cease to do justice and judgment, may be certain that they will not continue to enjoy the benefits of the covenant of grace. For all these reasons it is meet that the secret of Lord be with him Psalm 25:11.

18:9 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.