Genesis 21:1-7 “Now the LORD was gracious to Sarah as he had said, and the LORD did for Sarah what he had promised. Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. Abraham gave the name Isaac to the son Sarah bore him. When his son Isaac was eight days old, Abraham circumcised him, as God commanded him. Abraham was a hundred years old when his son Isaac was born to him. Sarah said, ‘God has brought me laughter, and everyone who hears about this will laugh with me.’ And she added, ‘Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.’”

I need to say a couple of things by way of introduction to this new chapter.

i] We have had to examine some tough providences. The previous two chapters are some of those grim and tragic chapters that you find in Scripture. You can put them alongside that horrible incident that is recorded in chapter 19 of the book of Judges. Those are some of the disturbing evils reported by the Holy Spirit, and yet there is one far uglier when men took the loveliest and best of men, and stripped him of his clothes and drove nails through his hands and feet and nailed him to a cross and taunted him for hours as he hung up there. I am involved in that action because it was my sins that did that to him. So that is why I am afraid of ignoring any passages in the Bible. I might start thinking sin is mere ‘bad taste’ and not something horribly rebellious against God, from  which only the atonement of the Son of God could deliver me. When I was at Cardiff University studying Biblical Studies our New Testament professor would not lecture on the dance of Herodias’ daughter and the beheading of John the Baptist. To him that incident was a degrading chapter. Now the world is looking at beheadings on websites, and no one knows how many lives are being ruined by dirty dancing. When the students at Cardiff came to those sixteen verses of Mark chapter six we sailed across them as if they were not there. That man believed that the Bible contained the word of God. He did not think that it was the word of God and sections he did not understand he discarded, sections like the preceding chapters. But even some evangelical preachers can routinely avoid them, but we believe that that ploy is very dangerous, and that those portions were also given by God for his glory and for the good of all his people.

So I have preached these four messages on the previous two chapters, and I am thankful to God that you at least are here today, but one person I spotted who arrived when I preached on the judgment that fell on Lot’s wife has not returned. I would not have chosen that passages as the first theme for a young person to hear as a baptism into my ministry, but God is in control of these matters. He has told me to preach everything in his word and I seek to do so as tenderly and faithfully as I can. I am not wiser than the Holy Spirit. That person might not have returned whatever I had preached on. Many do not.

These chapters are in the Bible to show us the exceedingly sinful nature of sin, even the remaining sin which is within us, the people of God. Sin is horrific, deceitful above all things, and the holiest man needs much divine grace day by day to keep out of hell. Grace is God’s power working in us to redeem us, and how we Christians need to focus on growing in grace to overcome the self-destructive tendencies of sin. Against the dark backdrop of Sodom and the behaviour of Lot, his wife, his daughters, and even the behaviour of Abraham, how brightly shines the mercy of God and the person of the Seed of the women, the Messiah, the Lord Jesus. The heart of man is desperately wicked, but Jesus Christ can save to the uttermost every filthy, rotten sinner who will fall into his outstretched arms. When God’s people refuse to obey the word of Christ almost anything can and will happen, even Abraham, the father of all who believe, can behave abominably towards his own wife. So we must take heed from these chapters and hold fast to the whole word of God. All Scripture is given by inspiration of God, but I say we are glad to reach chapter 21 of Genesis and the amazing birth of Abraham and Sarah’s son Isaac, for which event God has asked us to wait for so long.

ii] The other word for you, by way of introduction, is a comment on the unusual length of time it took for God to fulfil his promise to give Abraham and Sarah a son. Nine chapters have passed since chapter twelve of Genesis when God called Abraham out of Ur and sent him to the promised land announcing that though he was 75 he was going to become a father. Sarah was 65 when that promise was first made, and then it was not long, just a few months later, before it was repeated but this time strengthened by coming in the form of a solemn covenant. So we all might think, “Not long now”, but the years went by and there was no appearance of a baby. Then Abraham, having waited a further ten years, was foolish enough to listen to the voice of his wife – just as Adam had – and he went to Hagar, Sarah’s maid, who conceived quickly and had their son Ishmael. But this was not the son of the promise God had made. This was the son of the engineering of Abraham and the plotting of Sarah. Then fourteen more years passed – no children for all that time, just loads of waiting – and another messenger came from God repeating the promise, but still Abraham had to wait another twelve months until finally we’ve got here, Genesis chapter 21, when at the age of 100 Abraham and Sarah first heard the cry of a newborn baby – “Are we dreaming?’ – and they looked in wonder at the little boy and they could say, “Unto us a child is born; unto us a son is given.”

What was the point of having to wait 25 years? What a mystery, such a delay in the promise being fulfilled. What temptations came into Abraham’s life because of this long time. Twenty five years of waiting without any explanation, doing no more than any other married couple – how strange are God’s ways. For example, why should God wait to regenerate someone on his death-bed and not when he was fifteen when he could give his whole life to serving God? We must say, “Even so Father for so it seemed good in your sight.” God’s ways are not our ways. There was nothing Abraham could do to guarantee Sarah conceiving. There was nothing Sarah could do to produce a child. The arrival of this child was a result of sheer vertical sovereignty. Abraham was locked into God alone; he had to wait on Jehovah to give this son to them.

There isn’t one Christian who isn’t waiting on God to act and do many things for him, many temporal things and many spiritual things, who doesn’t ask if there is anything more that he or she can do? Perhaps some of you have been waiting more than 25 years for God to fulfil his promise. What do we say? I will pass on three things:

A] Be certain that God has made a promise concerning the matter. God had made a promise to Abraham and Sarah that they would have a son, but he had made no promise as to a specific time, not until one year before Isaac was born. Then they had to wait, and it was many years for the baby to be conceived and born. What kept them was the promise that the child was going to appear. I am saying, be sure you have a promise from the Bible and then you will have the patience to wait. For example, has God promised every Christian that he or she will get married? No. Has God promised every Christian couple that they will have children? No. Has he promised that every one of our children will be converted? No. Has he promised that every one of us will recover from every illness we have? No. That we will live a long life? No. That we will see a great awakening? No. That he will return during our lifetime? No.
We have no divine promises concerning any of those matters. However, he has promised that he will supply all our needs. He has promised that all things will work together for our good. He has promised that nothing will separate us from his love in Jesus Christ. He has promised us that as our days so will our strength be. He has promised us that if he has begun a good work in us he will complete it. He has promised us the resurrection of the body and reunion with all those who know the Lord. He has promised us that one day he will come again, though he has not told us when. We have his promises concerning these things and so we can be sure that our eyes will see their completion. So we can wait, standing on the promises of God.

B] Go on trusting God until all his promises have been fulfilled. The greatest troubles that were to come into Abraham’s life came because of a failure to trust what the Lord had said, especially that he would take care of accomplishing what he had said. If we doubt God’s ability and willingness to give us what he’s promised at his time, then we can begin to feel bitter and resentful, and we will do things our way. Jesus Christ is the same yesterday, and today and for ever, and Peter and the other disciples got into the most serious trouble when they did not trust him when he gave them his warnings and his encouragements. Rely on him; he will provide the best way for our lives. If nothing is happening it is because the best time, the set time, has not yet come. We must trust in the Lord’s plan. Often we say, “I do not know, but I know that God knows.”

C] Keep in communion with God. For fifty years Abraham and Sarah had shared their marriage bed and often quietly prayed that this time would result in the promised child being born, but every month the answer came, “No.” For about 300 times God’s word to them had been, “Not yet.” What a trial! Then 300 more times of living under the definite promise of a coming child, and still “Not yet” was the providential word. 60 times would have been a test, but 600 . . . They had to keep on talking to God about his promise and asking when it was going to be fulfilled, but prayer is far more than supplication. Prayer is also submission; so one constant prayer from the bottom of our hearts has to be, “Not my will, but yours, Lord.” Another God-delighting prayer is thanksgiving that Jehovah was the living God and he had made his promises. Let them delight themselves in him and his promise to them; they were going to have a child in God’s time. God has said it and that settled it. We can always bless God in the face of every delay that our Saviour, the Lord Jesus, has all authority in heaven and earth and he is working all things after the counsel of his own will. That is an active display of our faith; it demonstrates to God our confident expectation that his awesome power will give us what he has promised us.


i] Isaac was born to Sarah. Look at the language, “The Lord was gracious to Sarah as he had said, and the Lord did for Sarah what he had promised. Sarah became pregnant and bore a son to Abraham in his old age” (vv.1&2). It is so brief a birth announcement; it is almost peremptory. God worked, as he said he would, and a son was born to Sarah. Then life and its tensions went on. That is the Christian life isn’t it? Something that you have prayed for over decades finally happens, and very quickly you accept it and there a hundred other things happening. People are converted, they are married, after a long delay they have a baby, and life goes on. Man’s chief end is to glorify God in all of life.

Notice that there is no mention of Abraham being in any way responsible for the begetting of Isaac, though he was obviously the father. If they could have taken a DNA test then they would have said, “100% match.” But he had no power alone to produce this child. Moses reminds us again in verse five that he was a centenarian. He might visit Sarah but only the Lord was mighty enough to grant a begetting. That which was conceived in Sarah was of God, and this sounds so much like the birth of Jesus, the true Seed of Abraham, the Messiah. So you see this long delay in the appearance of Isaac, and the supernatural manner of Isaac’s coming is preparing us for 2000 years of waiting for Jesus to appear. Hannah and Simeon were waiting in the Temple of Jerusalem for the coming of the promised Son of the woman – for thousands of years there had been this patient waiting by the elect. The actual coming prepares us for a similar miraculous arrival of the Lord Jesus. In both cases we meet the long delay and a woman who could not conceive, one woman because she was ancient and barren, the other because she was a virgin. Both conceived by the supernatural activity of God after many years had gone by. The Lord visited old Sarah, and the Lord visited young Mary.

When our text in Genesis was translated into Greek 300 years before Christ the word the translator used for the Lord being gracious to Sarah was that the Lord ‘visited’ her and when Luke described Mary conceiving he used that same word. Mary says to the angel Gabriel, “How can I conceive seeing I have not known a man?” Gabriel replies, “The Holy Spirit will come upon you.” That is the same word that we find here in Genesis 21. The Holy Spirit will overshadow you. The Holy Spirit will visit you. With Sarah God helped an aged couple do what no couple of such an age had ever done before or since; with Mary God enabled Mary to have a child though she was a virgin. The link between Mary and aged Sarah was underlined in the words of the angel to Mary, “And behold Elizabeth your relative has also conceived a son in her old age; and this is now the sixth month for her who was called barren. For with God nothing will be impossible!” Nothing whatsoever.

So this event packed into these few words at the beginning of chapter 21 is momentous and we see that in the actual terminology used here. The Lord is not often described as ‘visiting’ his people, in fact just three times. This is the first, and then when they were slaves in Egypt we are told that God visited them, and then again God visited Hannah, another barren woman, and she gave birth to Samuel the prophet. So there were these three momentous visits, the first to bring in the promised son and begin the line of the people of God, the seed of Abraham; the second occurrence of the word was in delivering his people from bondage in Egypt and inaugurating the age of the law, and the third, with the birth of Samuel, inaugurated the birth of the prophets. Then in the New Testament God brings in the Messiah by visiting Mary. Only in such momentous times does God ‘visit’ his people, and so the unusual language here is saying to us, “Prick up your ears and really notice that the birth of Isaac is one of the great events in human history.” So Isaac was born to old Sarah.

ii] Isaac was born as God had promised. See how Moses insists on this in the repetition of the opening verses [I have replaced the pronound ‘he’ with the name of the Lord Jehovah; “Now the Lord was gracious to Sarah as the Lord had said, and the Lord did for Sarah what the Lord had promised. Sarah became pregnant and bore a son to Abraham in his old age, at the very time the Lord had promised him.” God was totally faithful to what he had promised. He was abundantly faithful down to the minutest detail. He visited Sarah as he had said he would. He came to her at the very time he had promised her one year earlier. He had promised he would. He has assured Abraham that his descendants would be as numerous as the stars in the heavens and here was the necessary earnest – the down payment – of that vast progeny. He had announced that it would be from Ab
raham’s own body a child would be begotten. “Sarah your wife shall bear you a son.” He had repeated that promise, and when Sarah had laughed God had simply asked her a question, “Is anything too hard for the Lord?” If God had not kept his word then that would have been the cosmic shock. That would have been devastating, but she had a son “at the very time God had promised” (v.2). In no way was this child a result of Sarah’s time in Abimelech’s harem. It was Abraham who became a father as God said he would. It is as if Moses had to disclose to his readers the fall of Abraham in chapter 20 for a solemn warning, but then he is at pains to affirm that this boy did not have Abimelech as his father. See the emphasis; “Sarah became pregnant and bore a son to Abraham . . . Abraham gave the name Isaac to the son Sarah bore him . . . Abraham was a hundred years old when his son Isaac was born to him” (vv. 2,3&5). So God performed the mercy promised to our fathers and remembered his holy covenant, the oath which he swore to our father Abraham.


i] Abraham named his son ‘Isaac.’ People call their children strange names. I know of an American who loved hunting with a passion, and he named his two sons, ‘Hunter’ and ‘Fisher.’ I have thought, what if he accidentally shot someone when hunting and filled with remorse vowed never to hunt again? Yet he has these two sons with those names reminding him of his past obsession which had led to such tragic consequences. Think of that man when you read of what this boy was called. The name ‘Isaac’ means ‘he will laugh,’ and it is the name that God chose for him; “you will call him Isaac” (Gen. 17:19). What a strange name, ‘he will laugh.’ It sounds to us like a Red Indian name, more like the son of Hiawatha than the son of Abraham, but years earlier God had commanded the old man to give this name to his son because Abraham had dared to laugh at God’s promise. “Right, you call the child ‘he will laugh’” God said, and Abraham did that calling him, “Isaac!” for the rest of his days. It was a humbling name for Abraham but there was a definitive, new obedience in Abraham though it has taken years to develop.

Let me just highlight this name by another comparison. At one of his other earlier bursts of defiance Abraham had slept with Hagar and they had had a son whom Abraham named in a defensive religious kind of way, ‘Ishmael,’ that is, ‘God hears.’ That is an ill-chosen and immodest name of hollow piety – like the people of South American countries who call their sons ‘Jesus.’ Like them Abraham was proclaiming his faith, but in fact there was no faith concerning this birth. Abraham had failed to wait on God. He had grown exasperated with God, and now in this name ‘Ishmael’ he is pretending that God was vindicating the decision he and Sarah had made to have a son by the servant girl. The act was in fact more like sexual abuse than the obedience of faith – even though the act was culturally acceptable and common then. Now, years later, the true seed of the promise has been born to him and Sarah, but instead of Abraham choosing another imposing name like ‘God lives’ or ‘God keeps his word’ he has to take the name God gives for his son and name the boy ‘he will laugh’ after his laughter of unbelief and he does so at the command of God. What a perplexing situation. Do you see it? On the one hand Ishmael, the child of unbelief, is the one who bears the name of faith, ‘God hears’ – quite falsely, while on the other hand Isaac, the child of faith, is bearing the name of unbelief, ‘he will laugh.’ But we will come to see how that name Isaac was redeemed.

So here we see the new spirit in Abraham, obediently accepting God’s commandment and giving this long awaited son this name ‘Isaac’ with its built-in rebuke. Abraham is submitting to God’s command. Abraham is doing what God said; the son of the promise has been born as God said he would be, and believing, he obeys. When you see God keeping his promises to you, sometimes in quite remarkable ways, doesn’t this put metal in your backbone to do everything in accordance with the good and acceptable and perfect will of God? But there was one more sign of obedience in Abraham’s life:

ii] Abraham circumcised his son Isaac.  God commanded him to do this and Abraham did it, because of Abraham’s faith in God believing that he and the generation that would follow him were all in a covenant of grace instituted by God. In all the nations of the world they alone were loved by God. They were the covenant people, and circumcision was an outward mark of that covenant. But when the final true Seed of the women was born, the son of Abraham, the son of David, the son of Mary, Jesus the Christ, then our Lord at eight days old was also circumcised. Though he had no sin that needed to be mortified and to be cut out of his life yet he allowed himself to be circumcised. That circumcision declared Jesus’ solidarity with us. Christ who was holy and harmless and undefiled had taken a sinner’s religion to redeem those who were bone of his bone and flesh of his flesh.

In his circumcision Jesus Christ the Seed of the woman proclaimed how he would deliver us from the curse, by himself becoming the curse for us. That is what Paul says. At the moment of his circumcision Jesus was also given a name un-chosen by his parents but it was the name that God had selected of ‘Jesus.’ His circumcision is the visible pledge of his saving purpose, coming into the world to save his people from their sins, by himself being made a curse for us, by being cut off at the cross. Cut off from a living, loving fellowship with his Father, entering the lake of fire while bearing our sin. That’s why we are able to say that his circumcision saves us because it was the sign of his going to the cross for us. Though he was only eight days old he immediately began to do the work his Father had given him to do.

At the cross, Jesus fulfilled the rite of circumcision for all time. The judgment and the curse on creation were cleared once and for all when he was cut off on Golgotha and one day yet to come this cosmic deliverance will be manifest. That’s why circumcision is no longer a requirement for Christians – because we have received our circumcision in union with Christ. “In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ, buried with Him in baptism…” (Col. 2:11&12), that is, in union with him we are delivered from the curse. Christ is the last physical seed to whom the promises were made in Abraham’s covenant line. There is no more physical seed beyond Christ to whom the promises can apply. The right to be called the children of God is no longer given to those who are born “of natural descent, nor of human decision, or a husband’s will” (Jn. 1:13), but who are born of God. So here are the two book-ends of the Abrahamic covenant, Abraham and Jesus Christ. They are the recipients of the covenant promises, Abraham was the first to receive the promises, and Christ as ‘his seed,’ is the last. The final heir to the promises has now come in Jesus Christ so that “the promise by faith in Jesus Christ might be given to those who believe” (Gals. 3:22). Christ is the consummation of Abraham’s physical seed. He is the final heir to the Abrahamic promises and only through personal faith in him can anyone else inherit them; it is not through your parents’ faith. There are no more physical seeds left in the covenant line. In Christ the physical lin
e stops, even as the spiritual line continues.


Abraham has his boy, but he has to call him “he will laugh.” He is thrilled with the baby, less thrilled with the name, but Sarah does not only treasure these things in her heart, she speaks up and she says to Abraham and to all listening, “God has brought me laughter, and everyone who hears about this will laugh with me” (v.6). 75 years of barrenness have ended. Twenty-five years of waiting for the promise to be fulfilled. What a wonderful name for our son. A girl born under those circumstances would be called ‘Joy’. Like so many wives of religious gentlemen her words cheer and lift her husband, but she looks outside her household and thinks of everyone who hears and says to their families, “Wonderful news! After twenty five years of waiting for what God had promised them Abraham and Sarah have become parents. They have a little boy and they have named him “he will laugh.” What an unusual but suitable name!” Abraham’s minor embarrassment about the name was quickly turned to delight. The Lord Jesus was speaking about the old patriarch’s delight when he said, “Abraham rejoiced to see my day, and he saw it and was glad.” His own son was held in his arms and so the great Son, the Seed of the woman, would surely come.

So here we see Sarah rejoicing at the goodness of God and again we see this psalm fulfilled, “Rejoice, O highly favoured one, the Lord is with you; blessed are you among women. God has made you laugh with joy.” Once upon a time the only laughter heard in the tents of Abraham and Sarah about their offspring was sly laughter against them. No doubt Sarah herself had felt many days of reproach as Mrs. Barren Wife. But now the laughter is only pure joy and those who laugh, laugh with her at God’s kind providence. The Lord has turned a reproach into a blessing. Who would have said to Abraham, “Now mark my words, your Sarah will yet become a mother?” Come on! You are living in cloud-cuckoo land. She is almost 90!”

It is marvelous, that Sarah should nurse children, that she should bear Abraham a son in his old age. Who could have predicted such a thing? Yet we know the answer. It’s in the first verse: the Lord was gracious to Sarah as he had said. God could. God did. Only God could have. With men it was impossible. Abraham had done what he could and should for 25 years. Any person would have said, “Abraham, you’ve got to resign yourself to this. You’re old. Your wife’s also barren. You’re not going to have a child. It’s not going to happen.” It would be cruel to tell them any different, wouldn’t it? How wise seems the foolishness of men! How foolish seems the wisdom of God! As Bill Baldwin says,

“Yet it is God’s wisdom that is vindicated here against the foolish wisdom of men. Now that Sarah has seen Isaac, now will Sarah believe God’s promises even when all her instincts and intuitions and the counsel of men tell her such things do not occur? Now that we have seen Christ crucified, yet raised again and seated at God’s right hand, now will we walk by faith rather than sight. Now will we trust God’s promises rather than what our eyes tell us.

“How impossible do all God’s promises seem to those who look at them rationally! We are surrounded by wickedness, thieves and murderers and fornicators and adulterers and idolaters and blasphemers. Haters of parents. Haters of God. Is God really in control? Is Christ really reigning? Shall we who die really be raised up? Will this world, which goes on as it always has, really come to an end? Will a world which we cannot see then really come down out of heaven as our eternal dwelling? None of this is logically deducible from what our eyes tell us. But God, who has been so faithful in Christ, will he not do the rest? Let us walk and live in that faith.

“God has given Sarah a son, Isaac. Can she doubt that now he will also freely with him give her all his promises?  From Isaac a great nation will be born. In him all the families of the earth will be blessed. The covenant given to him will last forever. God has given us his only son, Christ Jesus. How will he not also with him freely give us all things? That even though we die, yet we shall live. We shall be vindicated in the day of Christ Jesus. While we wait upon him, he makes intercession for us. So nothing can separate us from the love of God. It is expressed in Jesus Christ.”

Charles Haddon Spurgeon observed, “The more we study the words of grace, the more grace we derive from the words.” So if you’re having a struggle today trusting in God’s goodness and faithfulness, then maybe you need to do what Spurgeon suggested and study again the words of grace. Rehearse the promises of God that he has made to you and to every Christian; meditate on them; dwell on them; remember his faithfulness; and then determine by God’s grace to trust him at his word for the faithful God keeps his word.

20th September 2009    GEOFF THOMAS