Isaac is Born

The first two verses of Genesis 21 tell us three times that God kept His word. As He had said. “The Lord visited Sarah as He had said, and the Lord did for Sarah as He had spoken. For Sarah conceived and bore Abraham a son in his old age, at the set time of which God had spoken to him” (21:1-2). Sarah's baby was not luck, and Abraham and Sarah did not make it happen. It was God doing exactly what He had promised. Twenty-five years. Abram was seventy-five when he left Haran because God told him to (12:4). He is a hundred now (21:5). Twenty-five years passed between the promise and the baby. In between came a famine, a trip to Egypt, the split with Lot, the plan with Hagar, and thirteen more years of waiting. Through all of it, God had not forgotten. The set time. A year earlier God had put a date on it: “whom Sarah shall bear to you at this set time next year” (17:21). He said it again at Mamre: “At the appointed time I will return to you” (18:14). God was not running late for twenty-five years and then hurrying to catch up. The date was His all along. So when God seems slow to you, remember these two verses. Every word He had spoken came true, and it came on the day He had chosen.

In verses 3 and 4, Abraham does two things, and both are exactly what God told him to do. The name was not Abraham's idea. “Abraham called the name of his son who was born to him — whom Sarah bore to him — Isaac” (21:3). A year earlier God had said, “you shall call his name Isaac” (17:19). Abraham does not pick a family name or something grand. He uses the name God gave, and Isaac means “he laughs.” Every time Abraham called his son in for dinner, he was saying the word for the laugh he had laughed on his face in 17:17. The mark was not Abraham's idea either. “Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him” (21:4). That is the instruction of 17:12, kept to the day. This time there was no plan of his own. Back in chapter 16, Abraham went along with a plan God had never given, and it hurt everybody in the house. Here God speaks, and Abraham simply does what God said. Faith is not only believing that God will keep His promises. It is also doing what He says while you wait for them, and after He has kept them.

Verse 5 tells us plainly how old Abraham was: “Now Abraham was one hundred years old when his son Isaac was born to him” (21:5). Everyone knew what that meant. Abraham and Sarah knew it too. Abraham had said it himself in 17:17: “Shall a child be born to a man who is one hundred years old? And shall Sarah, who is ninety years old, bear a child?” Sarah said much the same in 18:12. Both laughs were about age. The New Testament says the same thing. Paul says Abraham “did not consider his own body, already dead (since he was about a hundred years old), and the deadness of Sarah's womb” (Romans 4:19). Hebrews says Isaac came “from one man, and him as good as dead” (Hebrews 11:12). Abraham's body could not give life anymore, but God could. So only one person could get the credit. Nobody could look at Isaac and say Abraham had managed it, or that Sarah had found a clever way around the problem, the way she had tried in chapter 16. Paul says Abraham was “fully convinced that what He had promised He was also able to perform” (Romans 4:21). The day Isaac was born, everyone could see that Abraham had been right to trust God. When God does what only God can do, all the thanks go to Him.

In verse 6, Sarah's words play on her son's name, and her old laugh becomes a brand-new one. The first laugh was behind a tent door. “Sarah laughed within herself” (18:12). It was a private laugh at a promise that sounded ridiculous. When God asked about it, she was afraid and said she had not laughed (18:15). The second laugh is out loud, and she says who caused it. “God has made me laugh” (21:6). Sarah does not take the credit for her joy. She says God gave her the laugh. It is the same word and the same woman, but now it is joy instead of doubt. God did not only keep His promise to Sarah. He changed her laugh. And it is meant to spread. “All who hear will laugh with me.” Good news that stays inside one tent is not finished. Psalm 126:2 says the same thing about the day God rescues His people: “Then our mouth was filled with laughter… Then they said among the nations, ‘The Lord has done great things for them.’” Then a feast. When Isaac was weaned, “Abraham made a great feast” (21:8). In that world children were often nursed for two or three years, so this was a toddler, and the promised son was growing up in front of everybody. The right answer to a kept promise is the one Sarah gave: joy, said out loud, so that other people can share it.