Few under the Old Testament were brought into the world with such expectation as Isaac was, not for the sake of any great person eminence at which he was to arrive, but because he was to be, in this very thing, a type of Christ, that seed which the holy God had so long promised and holy men so long expected. In this account of the first days of Isaac we may observe,

I. The fulfilling of God’s promise in the conception and birth of Isaac, Gen. 21:1, 2. Note, God’s providences look best and brightest when they are compared with his word, and when we observe how God, in them all, acts as he has said, as he has spoken. 1. Isaac was born according to the promise. The Lord visited Sarah in mercy, as he had said. Note, No word of God shall fall to the ground; for he is faithful that has promised, and God’s faithfulness is the stay and support of his people’s faith. He was born at the set time of which God had spoken, Gen. 21:2. Note, God is always punctual to his time; though his promised mercies come not at the time we set, they will certainly come at the time he sets, and that is the best time. 2. He was born by virtue of the promise: Sarah by faith received strength to conceive Heb. 11:11. God therefore by promise gave that strength. It was not by the power of common providence, but by the power of a special promise, that Isaac was born. A sentence of death was, as it were, passed upon the second causes: Abraham was old, and Sarah old, and both as good as dead; and then the word of God took place. Note, True believers, by virtue of God’s promises, are enabled to do that which is above the power of human nature, for by them they partake of a divine nature, 2 Pet. 1:4.

II. Abraham’s obedience to God’s precept concerning Isaac.

1. He named him, as God commanded him, Gen. 21:3. God directed him to a name for a memorial, Isaac, laughter; and Abraham, whose office it was, gave him that name, though he might have designed him some other name of a more pompous signification. Note, It is fit that the luxuriancy of human invention should always yield to the sovereignty and plainness of divine institution; yet there was good reason for the name, for, (1.) When Abraham received the promise of him he laughed for joy, Gen. 17:17. Note, When the sun of comfort has risen upon the soul it is good to remember how welcome the dawning of the day was, and with what exultation we embraced the promise. (2.) When Sarah received the promise she laughed with distrust and diffidence. Note, When God gives us the mercies we began to despair of we ought to remember with sorrow and shame our sinful distrusts of God’s power and promise, when we were in pursuit of them. (3.) Isaac was himself, afterwards, laughed at by Ishmael (Gen. 21:9), and perhaps his name bade him expect it. Note, God’s favourites are often the world’s laughing-stocks. (4.) The promise which he was not only the son, but the heir of, was to be the joy of all the saints in all ages, and that which would fill their mouths with laughter.

2. He circumcised him, Gen. 21:4. The covenant being established with him, the seal of the covenant was administered to him; and though a bloody ordinance, and he a darling, yet it must not be omitted, no, nor deferred beyond the eighth day. God had kept time in performing the promise, and therefore Abraham must keep time in obeying the precept.

III. The impressions which this mercy made upon Sarah.

1. It filled her with joy (Gen. 21:6): “God has made me to laugh; he has given me both cause to rejoice and a heart to rejoice.” Thus the mother of our Lord, Luke 1:46, 47. Note, (1.) God bestows mercies upon his people to encourage their joy in his work and service; and, whatever is the matter of our joy, God must be acknowledged as the author of it, unless it be the laughter of the fool. (2.) When mercies have been long deferred they are the more welcome when they come. (3.) It adds to the comfort of any mercy to have our friends rejoice with us in it: All that hear will laugh with me; for laughing is catching. See Luke 1:58. Others would rejoice in this instance of God’s power and goodness, and be encouraged to trust in him. See Ps. 119:74.

2. It filled her with wonder, Gen. 21:7. Observe here, (1.) What it was she thought so wonderful: That Sarah should give children suck, that she should, not only bear a child, but be so strong and hearty at the age as to give it suck. Note, Mothers, if they be able, ought to be nurses to their own children. Sarah was a person of quality, was aged; nursing might be thought prejudicial of herself, or to the child, or to both; she had choice of nurses, no doubt, in her own family: and yet she would do her duty in this matter; and her daughters the good wives are while they thus do well, 1 Pet. 3:5, 6. See Lam. 4:3. (2.) How she expressed her wonder: “Who would have said it? The thing was so highly improbable, so near to impossible, that if any one but God had said it we could not have believed it.” Note, God’s favours to his covenant-people are such as surpass both their own and others’ thoughts and expectations. Who could imagine that God should do so much for those that deserve so little, nay, for those that deserve so ill? See Eph. 3:20; 2 Sam. 7:18, 19. Who would have said that God should send his Son to die for us, his Spirit to sanctify us, his angels to attend us? Who would have said that such great sins should be pardoned, such mean services accepted, and such worthless worms taken into covenant and communion with the great and holy God?

IV. A short account of Isaac’s infancy: The child grew, Gen. 21:8. Special notice is taken of this, though a thing of course, to intimate that the children of the promise are growing children. See Luke 1:80; Luke 2:40. Those that are born of God shall increase of God, Col. 2:19. He grew so as not always to need milk, but was able to bear strong meat, and then he was weaned. See Heb. 5:13, 14. And then it was that Abraham made a great feast for his friends and neighbours, in thankfulness to God for his mercy to him. He made this feast, not on the day that Isaac was born, that would have been too great a disturbance to Sarah; nor on the day that he was circumcised, that would have been too great a diversion from the ordinance; but on the day that he was weaned, because God’s blessing upon the nursing of children, and the preservation of them throughout the perils of the infant age, are signal instances of the care and tenderness of the divine providence, which ought to be acknowledged, to its praise. See Ps. 22:9, 10; Hos. 11:1.