As He Had Said

Genesis 21 opens with a sentence that sounds almost too simple: “The Lord did for Sarah as He had spoken” (21:1). Twenty-five years of waiting, and the Bible sums them up as God doing what He said.

That sentence is not a one-off. The Bible keeps saying it at the big moments, about the whole of God's dealings with His people. When Joshua had finished dividing up the land, the Bible says: “Not a word failed of any good thing which the Lord had spoken to the house of Israel. All came to pass” (Joshua 21:45). Joshua said it again himself when he was old: “not one word of them has failed” (Joshua 23:14).

Hundreds of years later, King Solomon said the same thing. At the opening of the temple he stood in front of the whole nation and said, “There has not failed one word of all His good promise, which He promised through His servant Moses” (1 Kings 8:56). Solomon had all of Israel's history behind him, and that was his summary of it.

Why is God like this? Because of who He is. “God is not a man, that He should lie… Has He said, and will He not do? Or has He spoken, and will He not make it good?” (Numbers 23:19). People break promises because they forget, or change their minds, or find they cannot do it after all. None of those things can happen to God.

His word does the job it was sent to do. Isaiah compares it to rain and snow, which do not go back up to the sky until they have watered the ground and made things grow. “So shall My word be that goes forth from My mouth; it shall not return to Me void, but it shall accomplish what I please” (Isaiah 55:10-11).

And it is meant for you to lean on. Hebrews says that when God made His promise to Abraham, He swore by Himself, because there was nobody greater to swear by, “and so, after he had patiently endured, he obtained the promise” (Hebrews 6:13-15). It goes on to say God did this so that we “might have strong consolation” (Hebrews 6:18). The God who kept His word to Sarah is the God who makes promises to everyone who trusts Jesus. You can put your whole weight on what He says.

Every promise comes true in Jesus. Paul says, “all the promises of God in Him are Yes, and in Him Amen” (2 Corinthians 1:20). Every promise God ever made finds its yes in Jesus.

Genesis 21:2 tells us exactly when Isaac was born: Sarah bore a son “at the set time of which God had spoken to him.” Isaac did not just arrive eventually. He arrived on a date God had named a year before. God had marked that day long before it came.

God had put it on the calendar. In 17:21 God said Sarah would bear Isaac “at this set time next year.” At Mamre He said it again: “At the appointed time I will return to you” (18:14). So when the baby came, he was not late after twenty-five years. He was exactly on time for a date God had chosen.

That changes what waiting means. Waiting for someone who has forgotten you is miserable. It is different when the person has already chosen the day. The prophet Habakkuk was told this about God's promises: “The vision is yet for an appointed time… Though it tarries, wait for it; because it will surely come” (Habakkuk 2:3). Peter says the same: “The Lord is not slack concerning His promise, as some count slackness” (2 Peter 3:9).

The biggest set time of all. Paul uses the same idea for the birth of Jesus: “When the fullness of the time had come, God sent forth His Son” (Galatians 4:4). For hundreds of years after Abraham, God's people waited for the promised Savior. He came when the time God had chosen was full, not a day early and not a day late.

Two women who believed. When Mary went to visit her relative Elizabeth, who was also expecting a baby nobody had thought possible, Elizabeth said to her, “Blessed is she who believed, for there will be a fulfillment of those things which were told her from the Lord” (Luke 1:45). That is Sarah's story in one sentence, said to the mother of Jesus.

What to do with it. When you are waiting for God to do something, you are not waiting on someone who has lost track. David put it simply: “My times are in Your hand” (Psalm 31:15). The waiting is real, and it can be long. But the day belongs to God, and He keeps it. Abraham waited twenty-five years, and Hebrews says that “after he had patiently endured, he obtained the promise” (Hebrews 6:15).