THIRD SUNDAY OF ADVENT - GENESIS 21:1-7 - Righteous By the Son of Promise

Introduction

Have you ever noticed how beautiful the night sky is in winter? Colder air has less moisture, making the stars on a cloudless night in winter simply breathtaking. Granted, it is a lot more fun to lay out on the lawn on a warm July night, but you will never see a more dazzling display of constellations, planets (and even galaxies!) than a few minutes on a bitterly cold December night. If our family gets home after dark on a clear night, we are just as likely to walk back out of the garage to the driveway for a few minutes’ chilly stargazing—it’s worth it!

The Christmas season has a lot to do with night skies, darkness and stars—we hear it in many of our Christmas carols and hymns, don’t we?

Silent night, holy night…

O little town of Bethlehem, how still we see thee lie / Above thy deep and dreamless streets, the silent stars go by…

While shepherds watched their flocks by night, all seated on the ground...

O holy night, the stars are brightly shining...

But I want to suggest to you this morning that there is an Old Testament connection with Christmas and the night sky that we often overlook; but I believe that it is the single-most important element not only of Christmas, but of the entire testimony of the Scriptures. It is found a couple of chapters back from our text this morning—turn with me to Genesis 15 (page 10 in the pew Bible.) Abram has lived in Canaan for ten years at this point, having followed YHWH’s command to leave Ur of the Chaldees and come to a land that He was showing him. God promises Abram a great reward, but Abram cannot understand what reward he could have, seeing as he and Sarai his wife were childless:

Genesis 15:2–3 (LSB)

And Abram said, “O Lord Yahweh, what will You give me, as I go on being childless, and the heir of my house is Eliezer of Damascus?” And Abram said, “Since You have given no seed to me, behold, one born in my house is my heir.”

But YHWH goes on to promise him that he will have a son of his own someday—

Genesis 15:4 (LSB)

Then behold, the word of Yahweh came to him, saying, “This one will not be your heir; but one who will come forth from your own body, he shall be your heir.”

And not only would Abram have a son, but YHWH goes on to promise him that he would have countless descendants. In order to drive His promise home, He tells Abram to step outside his tent and look up into the night sky:

Genesis 15:5 (LSB)

And He brought him outside and said, “Now look toward the heavens, and number the stars, if you are able to number them.” And He said to him, “So shall your seed be.”

Abram looked up into the heavens—into a dark desert sky with no modern cities vomiting light pollution up into the night; the clear dry desert air shining with an impossible number of bright pinpoints of light, the Milky Way stretching like a celestial highway from horizon to horizon. And in that moment, Genesis 15:6 tells us

Genesis 15:6 (LSB)

Then he believed in Yahweh; and He counted it to him as righteousness.

And here is why I say that that holy night, the stars brightly shining in Abram’s eyes, represents the single-most important element not only of the Christmas story, but the entire story of redemption, when Abraham believed God’s promise to send him a son.

You can see this by the way that Genesis 15:6 flashes like a meteor across the rest of the Scriptures:

Romans 4:3 (LSB)

For what does the Scripture say? “Abraham believed God, and it was counted to him as righteousness.”

Romans 4:21–22 (LSB)

and being fully assured that what God had promised, He was able also to do. Therefore it was also counted to him as righteousness.

Galatians 3:6 (LSB)

Just as Abraham believed God and it was counted to him as righteousness,

James 2:23 (LSB)

And the Scripture was fulfilled which says, “And Abraham believed God, and it was counted to him as righteousness,” and he was called the friend of God.

The single greatest question that any man, woman or child can ever ask is, “How can I be righteous before God?” And the answer that we find in the Scriptures—from Genesis to Revelation—is that

You can only be RIGHTEOUS before God by FAITH in His PROMISED Son

God promised to send Abram a son—and Abram, believing that promise, was counted righteous before God. The great Reformation doctrine sola fide—by faith alone—is built on the united witness of the Old and New Testaments that Abraham’s righteousness was not predicated on anything he had done, but on believing what God said He would do.

Our text this morning gives us the account of the birth of Abraham’s promised son Isaac. My aim this morning is for us to search these verses together for demonstrations of what it looks like in the life of one who has been counted righteous by faith. What does it look like to have faith that is counted as righteousness? What are the characteristics of such a trust; how does it reveal itself in your life?

In the first two verses of Genesis 21 — the first characteristic of saving faith is that it is

I. Faith that RESTS in God’s PROMISES (Genesis 21:1-2)

Genesis 21:1–2 (LSB)

Now Yahweh visited Sarah as He had said, and Yahweh did for Sarah as He had promised. So Sarah conceived and bore a son to Abraham in his old age, at the appointed time of which God had spoken to him.

God had first made this promise to Abraham that night under the uncountable stars—a full fifteen years earlier. Abraham spent a decade and a half waiting on YHWH to keep His promise. See the faith of Abraham, who was content to wait for God to remember His promise

No matter how much TIME passes (cp. Heb. 11:9)

We saw the writer of Hebrews identify this aspect of Abraham’s faith in Hebrews 11:9:

Hebrews 11:9 (LSB)

By faith he [Abraham] sojourned in the land of promise, as in a foreign land, dwelling in tents with Isaac and Jacob, fellow heirs of the same promise,

Abraham was a foreigner in the land he had been promised to possess, and he died without ever possessing it. God promised to make him a father, and he waited fifteen years to see his wife deliver their son. Abraham was content to wait, resting in the assurance that God will always keep His promises.

But that is not to say that all of Abraham’s waiting was honoring to God, is it? Because no sooner had God promised Abraham a son in Genesis 15 but we see him and Sarai trying to bring about God’s promise on their own terms in Genesis 16--

Genesis 16:2 (LSB)

So Sarai said to Abram, “Now behold, Yahweh has shut my womb from bearing children. Please go in to my servant-woman; perhaps I will obtain children through her.” And Abram listened to the voice of Sarai.

The promise, after all, was that Abram would have a son from his own body—so, since Sarai said she obviously couldn’t have children, this must mean that Abram should have a baby with another woman. They couldn’t see how God could possibly keep His promise, and so they tried to take matters into their own hands—and the animosity and strife that grew up between Sarai and Hagar (and Ishmael and Isaac) was the result of their doubt.

But see here that God was faithful to keep His promise, and Abraham was still resting in God’s promises

No matter how much DOUBT interferes (Gen. 16:2-3; 18:15; 20:2)

Abraham is rightly exalted as the greatest example of saving faith in all of the Scriptures—you and I, after all, when we exercise saving faith are called “children of Abraham”. But take comfort, Christian, in the fact that our great forefather in the faith, Abraham, was a man who was often riddled with doubt and fear. He doubted God’s promise to bring him a son through his marriage to Sarai, and so he took Hagar. And just before Isaac’s birth, Abraham was so afraid of Abimelech king of Gerar, that he convinced Sarah to lie and say that she was his sister—which didn’t turn out well:

Genesis 20:2 (LSB)

And Abraham said of Sarah his wife, “She is my sister.” So Abimelech king of Gerar sent and took Sarah.

And in Genesis 18 we see that Sarah was prone to doubt as well—when YHWH repeated His promise to bring Sarah and Abraham a son, verse 12 says

Genesis 18:12 (LSB)

...Sarah laughed to herself, saying, “After I am worn out, shall I have pleasure, my lord being old also?”

Abraham laughed too—in Genesis 17:17:

Genesis 17:17 (LSB)

Then Abraham fell on his face and laughed and said in his heart, “Will a son be born to a man one hundred years old? And will Sarah, who is ninety years old, bear a son?”

—he laughed at the ridiculousness of it all: A baby being raised by two ancient old relics! But Sarah laughed out of scorn at the thought that she could ever have a child.

But look here at our text—no matter how many times Abraham and Sarah struggled with doubt or unbelief, no matter how many years stretched into decades of waiting. they still rested in God’s promise, and it was

Hebrews 11:11 (LSB)

By faith even Sarah herself received ability to conceive, even beyond the proper time of life, since she regarded Him faithful who had promised.

Did they doubt? Yes. Did they try to take matters into their own hands? Sure. Were they sinless in their trust? Not even close. But it was God’s faithfulness to them that counted. He kept His promise just as He said He would, doing for Sarah what He said He would do, and at just the right time.

Abraham’s faith rested in God’s promises, and so God counted it to him as righteousness. In the next three verses consider how Abraham trusted in God with a

II. Faith that DELIGHTS in God’s COVENANT (Genesis 21:3-5)

Genesis 21:3–5 (LSB)

And Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac. Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. Now Abraham was one hundred years old when his son Isaac was born to him.

God had instructed Abraham in Genesis 17 to name his son Yis-haq— “Laughter”. Abraham had laughed for joy (and Sarah had laughed with scorn) upon hearing the promise that they would have a son together. But when God instructs Abraham on what to name his baby, He specifically ties it to the covenant He had made with Abraham:

Genesis 17:19 (LSB)

But God said, “...Sarah your wife will bear you a son, and you shall call his name Isaac; and I will establish My covenant with him for an everlasting covenant for his seed after him.

On that starry night twenty-five years earlier, God had promised Abraham that he would be the father of an uncountable people—and by giving his son that name, Abraham was affirming that he believed that covenant.

What does this teach us about Abraham’s faith? Abraham’s faith delighted

To take the covenant IDENTITY God established (v. 3)

By naming his son according to God’s command, Abraham was affirming the covenant God made with him—he accepted his identity as the father of God’s covenant people. Abraham delighted to name his son “Laughter” because that name represented his inclusion in God’s covenant people. Naming his son Isaac was Abraham’s way of saying, “Yes! Sign me up! I am tremendously blessed to be included in God’s magnificent promises to me and my family!” No reservations, no second-guessing, no dragging his feet; Abraham delighted to be included in God’s covenant.

And you see in verse 4 the second way that he delighted in the covenant God had established with him:

Genesis 21:4 (LSB)

Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him.

His faith delighted to take the covenant identity God established, and he delighted

To take the covenant MARK God established (v. 4)

God had laid out the terms of His promises to Abraham in Genesis 17--

Genesis 17:4–6 (LSB)

“As for Me, behold, My covenant is with you, And you will be the father of a multitude of nations. “And no longer shall your name be called Abram, But your name shall be Abraham; For I have made you the father of a multitude of nations. “And I will make you exceedingly fruitful, and I will make nations of you, and kings will go forth from you.

And the sign of that covenant was circumcision—

Genesis 17:10 (LSB)

“This is My covenant, which you shall keep, between Me and you and your seed after you: every male among you shall be circumcised.

And so when Isaac was born, Abraham gave him that mark of belonging to those covenant promises. Once again, see Abraham’s wholehearted affirmation of the covenant; he delighted to obey God’s commands. Circumcision was a symbol of the fallen nature of mankind—it was a reminder of the indwelling sin that each of us were born with that needed to be cleansed, and “symbolized the need for a profoundly deep cleansing to reverse the effects of depravity” (MacArthur, J. F., Jr. (2006). The MacArthur study Bible: New American Standard Bible. (Ge 17:11). Thomas Nelson Publishers.)

What does it look like to have faith that is counted as righteousness? What are the characteristics of such a trust; how does it reveal itself in your life? We see here from Abraham’s life that it is faith that rests in God’s promises no matter how much time passes or how much doubt interferes. It is faith that delights to be included as one of the people of God’s covenant—to carry the name and to wear the mark of God’s promises.

In verses 6-7 the narrative turns to Sarah; now we hear her response to God’s faithful fulfillment of His promise:

Genesis 21:6–7 (LSB)

And Sarah said, “God has made laughter for me; everyone who hears will laugh with me.” And she said, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.”

Here is the third characteristic of faith that is counted as righteousness—is is

III. Faith that REJOICES in God’s REDEMPTION (Genesis 21:6-7)

Sarah’s struggles with unbelief sort of stand out in the account of God’s promises—as we said earlier, she scoffed when she heard the Angel of YHWH repeat His promise to Abraham about the birth of Isaac:

Genesis 18:11–12 (LSB)

Now Abraham and Sarah were old, advanced in age; Sarah was past childbearing. And Sarah laughed to herself, saying, “After I am worn out, shall I have pleasure, my lord being old also?”

But here in Genesis 21 her laughter is of a very different sort, isn’t it? Here in the fulfillment of God’s promise to her,

Bitter DISBELIEF becomes faithful DELIGHT (v. 6)

Genesis 21:6 (LSB)

And Sarah said, “God has made laughter for me; everyone who hears will laugh with me.”

In her disbelief, her laughter was mocking and full of hurt. “God is going to give me a baby? Yeah, right...” But now she has turned from laughing bitterly at herself and her pain to inviting others to laugh with her in joy! This is what saving faith does—faith that justifies makes its mark on your life in that what used to be your greatest bitter shame becomes a great joy to you because it magnifies the mercy of God in your life! Sarah spent her whole life embittered and cynical about her barrenness—but here, when God’s promise to her has been revealed in the birth of Isaac, all of that past pain and frustration becomes a spring of joy! “God has made laughter for me! He has turned the reason I mourned into the reason I laugh! Come, rejoice with me!!”

And further down in verse 7 see another characteristic of justifying faith:

Barren HOPELESSNESS becomes fruitful HAPPINESS (v. 7)

Genesis 21:7 (LSB)

And she said, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.”

Sarah points back to that very pain that she carried her whole life: “Nobody would ever have said that I would give my husband a baby—and look at us now!” That pain and cynicism was gone—replaced by joy in what the faithfulness of God had done for her. Sarah’s saving faith in God was demonstrated in the fact that she no longer identified herself by her unbelief. She had always been the “barren wife”—all of her contemporaries had children and grandchildren and great-grandchildren, but she was the barren one. When her husband came in from standing out under the stars that night to tell her that YHWH had promised him offspring too numerous to count, it had to stab her like a knife in the heart. No wonder she immediately turned to her servant Hagar to try to “fulfil” YHWH’s promise: “Well, it sure isn’t going to be me...”

But see how God redeemed that unbelief, that knot of despair and scorn and cynicism and disappointment that had settled in her heart like a stone—when He kept His promise to give her a son, all those years of barrenness and hopelessness were swept away, and she could no longer define herself by them! She wasn’t relegated to just being “Aunt Sarah” anymore—now she was Mom because of what God had done for her!

This is what faith that justifies looks like—it rests in God’s promises—no matter how long the wait, no matter how much doubt interferes. It delights in God’s covenant, rejoicing in the identity and mark of that covenant in your life. It is faith that rejoices in the redemption God provides, turning bitterness into delight and hopelessness into fruitful happiness.

What does God’s Word reveal about the nature of your own heart this morning? How do these Scriptures diagnose the nature of your “faith” this morning? Do you see faith that rests in God’s promises no matter how much time passes or how much doubt interferes? Or have you wearied of waiting on God and no longer believe that He can (or will) be faithful to you?

Do you find in your heart that kind of faith that delights to be named by His Name and delights to bear the mark of a Christian through baptism? Or is it too constricting to always have to be identified that way? Is your “Christian” label like one of those morale patches with the Velcro backing that you can rip off the sleeve of your jacket when it would be inconvenient for people to see it?

Do you find in your life the kind of faith that rejoices in God’s redemption of your life—your past pain and heartbreak and failure and hopelessness is a source of rejoicing for you because of how much God has done for you? You freely invite others to see the pain you had in your past so that they can laugh with you for all that He has done to redeem your sorrow? Or do you kind of like to hold on to that pain and bitterness, nurturing it in your heart, defining yourself by it, hanging on to the suffering and hardships of your past that shrivel you up into a cynical and sarcastic shell that spits out grudges against God and everyone else?

Beloved, the faith that justifies you before God does not come about by your own effort—it is a gift of God. Consider that Abraham believed God when He promised him that his offspring would be more numerous than the stars; he believed that God would send a miraculous son into the world to carry out that promise. But Abraham also knew that there was no way that baby was going to be born by any human power whatsoever! If that Promise God made was going to come true, it was going to come about completely apart from any ability Abraham or Sarah could contribute!

In the same way, beloved, you cannot achieve the kind of righteousness God requires by mustering up the ability to please Him by your faith any more than Abraham and Sarah could have mustered up the ability to conceive, carry and deliver Isaac all on their own. The faith that made them righteous in God’s sight was the faith that believed God would do everything necessary for that promise to come true.

The miraculous son that YHWH promised Abraham and Sarah was a glimpse of the miraculous Son that He sent thousands of years later—millennia of waiting with patient hope for that Promised Son to arrive. And when He did arrive in that little town of Bethlehem—with the same ancient stars shining down on him that His father Abraham looked up at in faith—He came as “the guarantee of a far better covenant” (Heb. 7:22) than Abraham’s. John’s Gospel tells us that

John 1:14 (LSB)

And the Word became flesh, and dwelt among us, and we beheld His glory, glory as of the only begotten from the Father, full of grace and truth.

Isaac’s birth revealed YHWH’s faithfulness to His promise to Abraham; Christ’s birth revealed His faithfulness to all the world:

John 1:12–13 (LSB)

But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.

Beloved, it is not in your own fleshly power to shape your faith into righteousness before God—no amount of striving in your own power to be patient in faith or overcome doubt or replace bitterness with delight will get you anywhere. If you are coming to church and carrying your Bible and using all the right Christian language because you think by doing so you are achieving some kind of righteousness before God, then you will never enter the Kingdom of Heaven.

Because John says that it is the ones who believe on the Son of the Promise—Jesus Christ—who are given the right to become Children of God. Children of God—members of God’s covenant family—are not born of “the will of man”. You cannot will yourself into a right relationship with God—you are as barren and impotent as a hundred year old man and his ninety year old wife. It is only when you drop all your own attempts to be good enough and repudiate your unbelief and impatience and bitterness and anger and insubordination.

Years after his birth, Isaac was led by his father up Mount Moriah, carrying the wood that would be laid under him for his father to offer him as a burnt sacrifice. YHWH intervened on that day, sending a ram to be sacrificed instead.

But the day would come for Jesus when He would carry the wooden Cross that He was to be sacrificed on up that same mountain—and on that day, there would be no substitute for that Father to slay in place of His Son, because on that day the Son of God Himself was the Substitute for you and me.

It is only by the blood of that Sacrifice that you can be made righteous; only by believing in the Son of Promise that you can be made right before God. And when you believe in the death, burial and resurrection of the Son of God Jesus Christ the way that Abraham believed in the promise of YHWH—that there is nothing you can contribute to your salvation but the sin that made it necessary—then you will receive “grace upon grace” and a new heart full of faith that rests in God’s promises, delights in His covenant and rejoices in His redemption.

So lay down all those attempts to be good enough for God and trust wholly and completely in His promised Son for your righteousness. You can be right with God today (and every day of this life and the next) when you come—and welcome! to Jesus Christ!

BENEDICTION

Ephesians 3:20–21 (LSB)

Now to Him who is able to do far more abundantly beyond all that we ask or understand, according to the power that works within us, to Him be the glory in the church and in Christ Jesus to all generations forever and ever. Amen.

QUESTIONS FOR REFLECTION AND DISCUSSION:

What are some ways that Christmas is associated with nighttime—darkness, stars, etc? What was the significance of the night sky when God made His promise to Abram, and how does this relate to the coming of Christ?

What characteristics of Abraham and Sarah’s faith do you most closely identify with? What are some ways that these verses have caused you to examine your trust in God’s promises more closely?

What does it mean to “delight” in your identity as part of God’s covenant family? Does your public testimony as a Christian reveal a delight in Christ’s work for you? What are some things that keep us from being uncompromising in our bearing the Name of Christ in this world?

What are some ways that you are tempted to hold on, like Sarah, either to past hurts or continuing disappointments? How does faith in God’s promises through Christ transform those hurts into reasons for joy?