Abraham laughed and said, “How is it possible for a man who is a hundred years old and a woman who is ninety years old to have a child? Perhaps Ishmael could inherit all your promises to me.” 

God said, “No, Sarah will have a son and you’ll call his name Isaac. I’ll give my promises to him and his descendants, and I’ll be their God. And the whole earth will be blessed because of them. 

But I will bless Ishmael as well. I will also make him a great nation. Twelve tribes will come from him.” 

Sometime later, Abraham was sitting at the door of his tent. Suddenly he noticed three men standing nearby, and realized that one of them was the Lord. He rushed over to them and said, “Sirs, Please, come sit under this tree. I’ll give you some water so you can wash your feet. Then you can rest while I prepare a meal. After you have eaten, you may continue on your way.” 

They said, “Yes, we’ll stay for a while.” 

Abraham rushed into the tent and told Sarah to make some bread for his guests. He then went to the field and selected a choice calf and gave it to his servants so they could use it to prepare a meal. As soon as the food was ready, Abraham served it to his guests and then stood back and watched them eat. 

As they ate, the Lord said to Abraham, “Where’s Sarah, your wife?” 

“She’s in the tent.”

The Lord said, “I’ll come back in about a year. 

At that time Sarah will have given birth to a son.” Sarah was listening to this from inside the tent. She was ninety years old, so she laughed inside herself when she heard that she was going to give birth to a son. She said, “That’s impossible. I’m too old to give birth to a child.” 

The Lord asked Abraham, “Why did Sarah laugh? Is anything too hard for the Lord? I WILL come back, and she WILL have given birth to a child!” 

When Sarah heard this, she ran out and said, “Lord, I didn’t laugh!” 

“Ah, but you DID laugh!” 

Soon Sarah found that she was expecting a child.