Genesis 21:7

The story progresses in verse 3: ‘Abraham called the name of his son who was born to him, whom Sarah bore him Isaac.’ It’s hard to imagine what Abraham had been though in the last few years. A quarter of his life had been lived in the light of the promise of the child he now held in his arms. Twenty five years of waiting for a son by his wife was over. Abraham called him Isaac, just as God had commanded in 17:19. Isaac means ‘He laughs’. I love this part of the story, and it’s significant for reason’s we’ll come back to. You can imagine that upon the birth of the long awaited son Abraham would be full of laughter so maybe this was an obvious name. But why did God tell Abraham to name his son Isaac? I think, as we’ll see in a moment, this is part of how we make sense of this story today.

God’s plan is marching on. We notice again in verse 5 that we’re told ‘Abraham was a hundred years old when his son Isaac was born to him’. Why more repetition? Surely for the same reasons that there was repetition in verses one and two. One commentator says that ‘there is great emphasis in the repetition… For he thus retains his readers, as by laying his hand upon them, that they may pause in consideration of this great miracle.’ The next time we ask whether it’s possible for God to do something we need to really ask ‘how big is God?’ Here we see a huge God keeping His huge promises.

The last two verses are given to Sarah, and it’s probably a song. Verse six says: ‘God has made laughter for me, everyone who hears will laugh over me.’ With this miraculous visit and fulfillment, God has turned Sarah’s laugh of disbelief into a genuine laugh of joy. And, of course, as we’ve already seen, the name Isaac means ‘he laughs’. God wanted Isaac to be called Isaac so that every time Sarah looked at her son, she would remember what God has done, and laugh for joy about it. Not only Sarah would laugh, but those in her household and also, those who read this story. Israel would have been expected to laugh with a similar joy when they read this story, because, in a very real way, Isaac’s birth signaled the birth of the nation of Israel. If Isaac had never been born then there would have been no Israel, no nation of God’s people.

Like ancient Israel we can also laugh with joy at what God has done in our lives. Once we were not God’s people, now we are God’s people, once we did not call on His name to save us from our sin, no we can think of no other sort of life. Just as God miraculously called Isaac into existence He has miraculously called us into faith. This is why I started this morning asking why we were here. It’s so easy to get relaxed about being a Christian or coming to church, but our salvation is a breathtaking miracle. It’s a bit like flying. Imagine sitting in a metal tube a few miles above the surface of the earth and traveling at about six hundred miles an hour, only slightly slower than my voice is traveling to you right now. It should be the most thrilling way of traveling that we know, and yet, because flying is such a normal thing today we spend our time reading or watching movies or sleeping, and grumbling when our plane is delayed. We mustn’t let ourselves end up like this about the church, about knowing Jesus. We need to remember that our being saved is a joyful, miraculous thing. Like a ninety year old giving birth, it should be something that we barely dare to believe.

In verse seven Sarah’s song, and our story ends ‘and she said, who would have said to Abraham that Sarah would nurse children? Yet I have born him a son in his old age.’ Well Sarah’s right, who indeed would have thought this would happen. And yet it did. A son was born, then a nation, and then another Son.

Who would have thought that a virgin could have given birth? Who would have thought that a homeless carpenter was the Son of God? Who would have thought that His death would bring life to all who believed in Him? Jesus brings the final fulfillment of God’s promise to Abraham. Abraham was promised not just that he would father Isaac, but that he would father a multitude of nations. Jesus pours out His Spirit on his followers so that we would ‘make disciples of all nations.’ Jesus shed His blood for the nations that they might be saved. In the birth of Isaac, we see the initial fulfillment of God’s promise to make Abraham a multitude of nations, fulfilled in Jesus and then through us.

So why is Isaac’s birth recorded in the Bible? To stir up faith among God’s people at the wonderful work of our miraculous God. To leave Israel, and then the church, in wonder at what God has done in saving His people, so that we would laugh for joy like Sarah and not become tired in their love for the Lord.

To teach us that His promises are to be trusted. As we saw earlier, Abraham didn’t trust God’s promises and tried to make them work his own way. He didn’t believe that his aged wife could give birth, so he had a son by Hagar. He didn’t believe that God would keep him safe in a foreign land, so he told the king that Sarah was his sister and let him marry her. God wasn’t going to fulfill His promise though Ishmael because Ishmael was possible. Isaac was impossible! All of Abraham’s efforts only took him further away from what God was ding. All God requires of Abraham, and us, is to have faith in His promises.

To remind us that read now that God promised to make Abraham a father of many nations, through the death of Christ this has been made possible, and so to remind us of our responsibility to play our part in the great commission.