Long-looked-for comes at last. The vision concerning the promised seed is for an appointed time, and now, at the end, it speaks, and does not lie; 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 thin, 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, Gen 21:2. 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, Pe2 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, Luk 1:46, Luk 1:47. 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 Luk 1:58. Others would rejoice in this instance of God's power and goodness, and be encouraged to trust in him. See Psa 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, Pe1 3:5, Pe1 3:6. 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; Sa2 7:18, Sa2 7:19. 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 Luk 1:80; Luk 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, Heb 5:14. 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 Psa 22:9, Psa 22:10; Hos 11:1.

The casting out of Ishmael is here considered of, and resolved on. I. Ishmael himself gave the occasion by some affronts he gave to Isaac his little brother, some think on the day that Abraham made the feast for joy that Isaac was safely weaned, which the Jews say was not till he was three years old, others say five. Sarah herself was an eye-witness of the abuse: she saw the son of the Egyptian mocking (Gen 21:9), mocking Isaac, no doubt, for it is said, with reference to this (Gal 4:29), that he that was born after the flesh persecuted him that was born after the Spirit. Ishmael is here called the son of the Egyptian, because, as some think, the 400 years' affliction of the seed of Abraham by the Egyptians began now, and was to be dated hence, Gen 15:13. She saw him playing with Isaac, so the Septuagint, and, in play, mocking him. Ishmael was fourteen years older than Isaac; and, when children are together, the elder should be careful and tender of the younger: but it argued a very base and sordid disposition in Ishmael to be abusive to a child that was no way a match for him. Note, 1. God takes notice of what children say and do in their play, and will reckon with them if they say or do amiss, though their parents do not. 2. Mocking is a great sin, and very provoking to God. 3. There is a rooted remaining enmity in the seed of the serpent against the seed of the woman. The children of promise must expect to be mocked. This is persecution, which those that will live godly must count upon. 4. None are rejected and cast out from God but those who have first deserved it. Ishmael is continued in Abraham's family till he becomes a disturbance, grief, and scandal to it. II. Sarah made the motion: Cast out this bond-woman, Gen 21:10. This seems to be spoken in some heat, yet it is quoted (Gal 4:30) as if it had been spoken by a spirit of prophecy; and it is the sentence passed on all hypocrites and carnal people, though they have a place and a name in the visible church. All that are born after the flesh and not born again, that rest in the law and reject the gospel promise, shall certainly be cast out. It is made to point particularly at the rejection of the unbelieving Jews, who, though they were the seed of Abraham, yet, because they submitted not to the gospel covenant, were unchurched and disfranchised: and that which, above any thing, provoked God to cast them off was their mocking and persecuting the gospel church, God's Isaac, in its infancy, Th1 2:16, Note, There are many who are familiarly conversant with the children of God in this world, and yet shall not partake with them in the inheritance of sons. Ishmael might be Isaac's play-fellow and school-fellow, yet not his fellow-heir. III. Abraham was averse to it: The thing was very grievous in Abraham's sight, Gen 21:11. 1. It grieved him that Ishmael had given such a provocation. Note, Children ought to consider that the more their parents love them the more they are grieved at their misconduct, and particularly at their quarrels among themselves. 2. It grieved him that Sarah insisted upon such a punishment. "Might it not suffice to correct him? would nothing less serve than to expel him?" Note, Even the needful extremities which must be used with wicked and incorrigible children are very grievous to tender parents, who cannot thus afflict willingly. IV. God determined it, Gen 21:12, Gen 21:13. We may well suppose Abraham to be greatly agitated about this matter, loth to displease Sarah, and yet loth to expel Ishmael; in this difficulty God tells him what his will is, and then he is satisfied. Note, A good man desires no more in doubtful cases than to know his duty, and what God would have him do; and, when he is clear in this, he is, or should be, easy. To make Abraham so, God sets this matter before him in a true light, and shows him, 1. That the casting out of Ishmael was necessary to the establishment of Isaac in the rights and privileges of the covenant: In Isaac shall thy seed be called. Both Christ and the church must descend from Abraham through the loins of Isaac; this is the entail of the promise upon Isaac, and is quoted by the apostle (Rom 9:7) to show that not all who come from Abraham's loins were the heirs of Abraham's covenant. Isaac, the promised son, must be the father of the promised seed; therefore, "Away with Ishmael, send him far enough, lest he corrupt the manners or attempt to invade the rights of Isaac." It will be his security to have his rival banished. The covenant seed of Abraham must be a peculiar people, a people by themselves, from the very first, distinguished, not mingled with those that were out of covenant; for this reason Ishmael must be separated. Abraham was called alone, and so must Isaac be. See Isa 51:2. It is probable that Sarah little thought of this (Joh 11:51), but God took what she said, and turned it into an oracle, as afterwards, Gen 27:10. 2. That the casting out of Ishmael should not be his ruin, Gen 21:13. He shall be a nation, because he is thy seed. We are not sure that it was his eternal ruin. It is presumption to say that all those who are left out of the external dispensation from all his mercies: those may be saved who are not thus honoured. However, we are sure it was not his temporal ruin. Though he was chased out of the church, he was not chased out of the world. I will make him a nation. Note, (1.) Nations are of God's making: he founds them, he forms them, he fixes them. (2.) Many are full of the blessings of God's providence that are strangers to the blessings of his covenant. (3.) The children of this world often fare the better, as to outward things, for their relation to the children of God.