These heavenly guests (being sent to confirm the promise lately made to Abraham, that he should have a son by Sarah), while they are receiving Abraham's kind entertainment, they return his kindness. He receives angels, and has angels' rewards, a gracious message from heaven, Matthew 10:41.
I. Care is taken that Sarah should be within hearing. She must conceive by faith, and therefore the promise must be made to her, Hebrews 11:11. It was the modest usage of that time that the women did not sit at meat with men, at least not with strangers, but confined themselves to their own apartments; therefore Sarah is here out of sight: but she must not be out of hearing. The angels enquire (Genesis 18:9), Where is Sarah thy wife? By naming her, they gave intimation enough to Abraham that, though they seemed strangers, yet they very well knew him and his family. By enquiring after her, they showed a friendly kind concern for the family and relations of one whom they found respectful to them. It is a piece of common civility, which ought to proceed from a principle of Christian love, and then it is sanctified. And, by speaking of her (she over-hearing it), they drew her to listen to what was further to be said. Where is Sarah thy wife? say the angels. "Behold in the tent," says Abraham. "Where should she be else? There she is in her place, as she uses to be, and is now within call." Note, 1. The daughters of Sarah must learn of her to be chaste, keepers at home, Titus 2:5. There is nothing got by gadding. 2. Those are most likely to receive comfort from God and his promises that are in their place and in the way of their duty, Luke 2:8.
II. The promise is then renewed and ratified, that she should have a son (Genesis 18:10): "I will certainly return unto thee, and visit thee next time with the performance, as now I do with the promise." God will return to those that bid him welcome, that entertain his visits: "I will return thy kindness, Sarah thy wife shall have a son;" it is repeated again, Genesis 18:14. Thus the promises of the Messiah were often repeated in the Old Testament, for the strengthening of the faith of God's people. We are slow of heart to believe, and therefore have need of line upon line to the same purport. This is that word of promise which the apostle quotes (Romans 9:9), as that by the virtue of which Isaac was born. Note, 1. The same blessings which others have from common providence believers have from the promise, which makes them very sweet and very sure. 2. The spiritual seed of Abraham owe their life, and joy, and hope, and all, to the promise. They are born by the word of God, 1 Peter 1:23.
III. Sarah thinks this too good news to be true, and therefore cannot as yet find in her heart to believe it: Sarah laughed within herself, Genesis 18:12. It was not a pleasing laughter of faith, like Abraham's (Genesis 17:17), but it was a laughter of doubting and mistrust. Note, The same thing may be done from very different principles, of which God only, who knows the heart, can judge. The great objection which Sarah could not get over was her age: "I am waxed old, and past childbearing in the course of nature, especially having been hitherto barren, and (which magnifies the difficulty) my lord is old also." Observe here, 1. Sarah calls Abraham her lord; it was the only good word in this saying, 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. Thus must the wife reverence her husband, Ephesians 5:33. And thus must we be apt to take notice of what is spoken decently and well, to the honour of those that speak it, though it may be mixed with that which is amiss, over which we should cast a mantle of love. 2. Human improbability often sets up in contradiction to the divine promise. The objections of sense are very apt to stumble and puzzle the weak faith even of true believers. It is hard to cleave to the first Cause, when second causes frown. 3. Even where there is true faith, yet there are often sore conflicts with unbelief, Sarah could say, Lord, I believe (Hebrews 11:11), and yet must say, Lord, help my unbelief.
IV. The angel reproves the indecent expressions of her distrust, Genesis 18:13-14. Observe, 1. Though Sarah was now most kindly and generously entertaining these angels, yet, when she did amiss, they reproved her for it, as Christ reproved Martha in her own house, Luke 10:40-41. If our friends be kind to us, we must not therefore be so unkind to them as to suffer sin upon them. 2. God gave this reproof to Sarah by Abraham her husband. To him he said, Why did Sarah laugh? perhaps because he had not told her of the promise which had been given him some time before to this purport, and which, if he had communicated it to her with its ratifications, would have prevented her from being so surprised now. Or Abraham was told of it that he might tell her of it. Mutual reproof, when there is occasion for it, is one of the duties of the conjugal relation. 3. The reproof itself is plain, and backed with a good reason: Wherefore did Sarah laugh? Note, It is good to enquire into the reason of our laughter, that it may not be the laughter of the fool, Ecclesiastes 7:6. "Wherefore did I laugh?" Again, Our unbelief and distrust are a great offence to the God of heaven. He justly takes it ill to have the objections of sense set up in contradiction to his promise, as Luke 1:18. 4. Here is a question asked which is enough to answer all the cavils of flesh and blood: Is any thing too hard for the Lord? (Heb. too wonderful), that is, (1.) Is any thing so secret as to escape his cognizance? No, not Sarah's laughing, though it was only within herself. Or, (2.) Is any thing so difficult as to exceed his power? No, not the giving of a child to Sarah in her old age.
V. Sarah foolishly endeavours to conceal her fault (Genesis 18:15): She denied, saying, I did not laugh, thinking nobody could contradict her: she told this lie, because she was afraid; but it was in vain to attempt concealing it from an all-seeing eye; she was told, to her shame, Thou didst laugh. Now, 1. There seems to be in Sarah a retraction of her distrust. Now she perceived, by laying circumstances together, that it was a divine promise which had been made concerning her, she renounced all doubting distrustful thoughts about it. But, 2. There was withal a sinful attempt to cover a sin with a lie. It is a shame to do amiss, but a greater shame to deny it; for thereby we add iniquity to our iniquity. Fear of a rebuke often betrays us into this snare. See Isaiah 57:11, Whom hast thou feared, that thou hast lied? But we deceive ourselves if we think to impose upon God; he can and will bring truth to light, to our shame. He that covers his sin cannot prosper, for the day is coming which will discover it.