The fruit of faith - Genesis 21
This is a sermon by Peter Birnie from the Riverside Church service on 1st March 2026.
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Intro: (Slide 1) Have you ever asked yourself “Why is the world the way it is?” That question is asked on one level by many different types of people, and then on another level by Christians in particular.
- (Slide 2) Level 1, asked by all sorts of people is this; ‘why is the world so full of both good and bad?’ That is a good question and it demands a good explanation. What especially seems lacking in the explanation that atheists and humanists and reductionists give is a decent reason for the existence of good, the reality that many people will make huge sacrifices for the sake of others. If life really is simply survival of the fittest and the passing on of the most successful genetics, then this type of good is utterly illogical and incoherent. The bible explains good and bad in a far more satisfactory way than anything else (God is good, we are made in his image, we benefit from his common grace and goodness, and yet sin has turned us away from his rule and against him instead, poisoned the earth and put us under a curse). The bible’s description of and explanation for reality is one that matches our day to day experience. (There is good and there is bad and that makes sense).
- (Slide 3) Christians often ask a linked question but on a different level – our question normally sounds like this; ‘why are believers in Jesus so often persecuted so badly all around the world?’ The research shows that Christians are more persecuted than any other religion or any other belief system – a 2025 statement to the United Nations Human rights counsel from the European Centre for Law and Justice states this; “Christians are the most persecuted religious group around the world with more than 310 million Christians being subjected to extreme levels of persecution… Christians are arbitrarily arrested, attacked, assaulted, and killed because of their faith.” Believers in Jesus don’t just ask why there is both good and bad, they ask why they suffer more than anyone else, why, despite much of their faith causing them to care for others and make sacrifices to help others, the others often despise them and want to get rid of them.
(Slide 4) If that is your question here today, or if you do often wonder why it is difficult even in our culture to own the name of Jesus and be public with our faith, then Genesis 21 is here to help. In this part of the bible we see the great joy that God’s promises offer to the world, joy that should provoke a grateful response, and yet we also see that God’s people from the beginning have been opposed and that God’s promises from the beginning bring division as well as hope.
1) The promised child brings laughter (v1-7)
(Slide 5) Let’s begin in the passage by seeing the laughter that God’s promised child brings. Verses 1,3 and 6; “Now the LORD was gracious to Sarah as he had said and the LORD did for Sarah what he had promised… Abraham gave the name Isaac to the son Sarah bore him… Sarah said, ‘God has brought me laughter, and everyone who hears about this will laugh with me.” Isaac, “Son of laughter” – a wonderful name for an impossible baby. Sarah was barren her whole life, and now, decades after any woman would be able to get pregnant, at 90 years of age, Abraham and Sarah’s longed for, prayed for, promised baby, is born.
(Slide 6) I love verse 1 in particular and as a result it is on our handout as the memory verse this week, as a verse you could run over again and again in your mind, meditating on God’s faithfulness; “Now the LORD was gracious to Sarah AS HE HAD SAID and the LORD did for Sarah WHAT HE HAD PROMISED.” What we need to be clear on, and what will bring so much peace and joy to our lives, what will strengthen our obedience to God, is that this is always how God acts because of his unchanging nature, because of his utter holiness. The Triune God will always do exactly what he has said he will. He will always bring to pass what he has promised he will. Nothing is too hard for God – because everything in our existence has been brought into existence from nothing by God's word. What laughter and joy that Sarah got to experience as a result of God’s goodness. But should Abraham and Sarah not have simply taken God at his word all along?
(Slide 7) Should they not have just waited patiently for God to do what he said he would do? Should they not have just stood steadfastly on what God had promised to give them? Of course they should. How wonderful a privilege it was for Abraham in verse 4 to circumcise Isaac at 8 days old, just as God had commanded him to. But his whole life is more complicated than it should have been, and our world right now is far more divided than it could have been, had Abraham and Sarah just kept patiently waiting for God to do what God always does instead of going about things their own way.
(Slide 8) 2000 years after this event there were some shepherds looking after their sheep on a hillside near Bethlehem. And suddenly they weren’t alone – angels lit up the sky, proclaiming good news of great joy for all people. A promised baby was being born – a baby who would bring laughter and joy to people from all nations of the world. The ultimate “God will do what he has said, God will fulfil what he had promised.” And as a result of the birth, life, death and resurrection of Jesus, we have everything we need to joyfully trust God, to faithfully wait for him, to be at peace in all circumstances in our lives knowing that no matter how bad things may appear, God will always provide what is needed for his children, God will never leave us or forsake us, God will always be working all things for the good of those who love him. Should we who have our faith in Jesus not be laughing a bit more throughout life? Not pretending things don’t matter, not ignoring the weight of trials and opposition, but having hearts that realise we are blessed beyond measure because of Jesus (Betsy ten boom thanking God for the fleas!).
2) The promised line brings opposition and division (v8-21)
(Slide 9) What a challenge to be people of joy and laughter even in dark times – we have every reason to be so. Verses 8-21 are not filled with laughter and yet they help us in this desire to be joyful in Jesus by revealing to us what normal life looks like when you belong to God. The promised line brings opposition and division – we aren’t doing life and faith wrong when this is the case, it has always been the case. Isaac has just been weaned, so we are talking about a baby or a toddler when Abraham throws a feast to celebrate God’s goodness. I suppose it would have been an occasion filled with happiness but then we get verse 9; “Sarah saw that the son whom Hagar the Egyptian had borne to Abraham was mocking.” What could a toddler possibly do to deserve being mocked? Nothing. That is the point. It is not what this baby does, but rather who this baby is that draws the scorn of Ishmael.
(Slide 10) It may not seem much to us but actually, what we see from Ishmael in Genesis 21v9 is the beginning of a pattern that will lead God’s people to being oppressed and persecuted again and again throughout history, a pattern that produces untold numbers of sufferers and martyrs, a pattern that results in this Open Doors world watch list today. Sin has so infected the human heart and so turned us all against God’s good rule and character, that our natural response of enmity towards God provokes a similar natural response of enmity towards the people of God. That is what is happening in Genesis 21 as a 15 or 16 year old Ishmael mocks the promised gift that God has given (despite him being just a toddler).
And it is that pattern has wreaked misery in the world today as followers of Jesus, seeking to live like Jesus and love others, get treated in terrible ways throughout history and across geography. Belonging to the promised child brings opposition – it just does. Jesus said that people will hate believers because they hate him and people do hate believers.
In the next few verses the picture and the explanation for this are completed. The fact that there is a promised people brings division, there is no way around this. Sarah wants Abraham to get rid of Hagar and Ishmael, and though this isn’t compassionate, and though it distresses Abraham greatly (after all, Ishmael is his son), God speaks to Abraham and tells him to do what Sarah says (Slide 11), v12 and 13; “Listen to whatever Sarah tells you, because it is through Isaac that your offspring will be reckoned. I will make the son of the slave into a nation also because he is your offspring.” Here we have God’s sovereign choice that nobody can do anything about – Isaac is the child of promise and Ishmael is not.
But we also have God’s grace and faithfulness – Ishmael won’t simply fade away, he too will become a nation. In verses 14-21 we have Ishmael’s story – he isn’t the promised child, he scorns the promised child and so he must leave. But God’s mercy means he doesn’t die in the desert and instead he lives to become a nation, just as God declared.
(Slide 12) There are a few folk in this church with an intolerance to gluten. If you are one of those people then over the years you will have got really good at checking the ingredients list on any product that you eat.
The ingredients list will explain the consequences you are currently experiencing if you have not been able to resist a lovely looking cake at the drop in or a Mars bar at Life Group. (Slide 13) Look at the ingredients in this world that Genesis 21 makes clear;
- There is a promised child who brings opposition: as a pastor called Jonathan Griffiths writes; “Access to salvation blessings is tied to our response to the miraculous child of promise … The casting out of Hagar and Ishmael is a warning that God will not welcome those who do not welcome his son.”
- And there is a promised line which brings division: You are either part of the promised line or you are not. Choosing automatically brings division.
So should Christians be surprised by opposition and division in this world – no, of course not, look at the ingredients. Should Christians lose their joy and peace when people oppose them, hate them and persecute them – no, we are so privileged, in Christ, to belong to the line of the promised child. In the New Testament, in his second letter to the church in Corinth, Paul explains the expectations we are to have and the impact we will have on those around us if we belong to Jesus (Slide 14); “For we are to God the pleasing aroma of Christ among those who are being saved and those who are perishing. To the one, we are an aroma that brings death; to the other, an aroma that brings life.” Don’t let opposition and division because of Jesus get you down, instead keep living joyful gospel lives, speaking gospel truth to see others saved.
3) The promising God offers acceptance (v22-34)
(Slide 15) Because where we finish in the passage today is with the bright hope that God offers all the nations of the world. Yes, God’s promised child brings opposition, yes, God’s promised line brings division, but the truth of God’s plan of salvation from beginning to end is that the promising God offers people acceptance. Abimelek, a foreign king, has already had dealings with Abraham in chapter 20 and I wonder if your Life Group worked through the same thoughts as ours did? We were amazed at how well Abimelek treated Abraham, despite Abraham deserving the exact opposite. Now we know that the big answer is that God is sovereign and gracious so that is why Abraham was treated well, but as we get to 21v22 it seems to make a lot more sense from simply a human viewpoint; “At that time Abimelek and Phicol the commander of his forces said to Abraham, ‘God is with you in everything you do.’”
(Slide 16) “God is with you in everything you do.” Abimelek can see clearly that he isn’t just dealing with a man here, he is dealing with the God of heaven. And if we are thinking in terms of aroma of life or aroma of death, it seems here that Abimelek recognises that it will be one or the other as he deals with Abraham but more so as he deals with the God of Abraham. So he comes to deal carefully and well with Abraham – he wants to make a treaty, an agreement that will keep him and his people safe. He wants to be blessed by God and not cursed. Abraham agrees to the treaty and Beersheba becomes quite a significant place in the history of the people of God.
(Slide 17) Abimelek acts the way we pray the people around us will act as they watch us, as they think about our witness, as they consider the way that we live and the God whom we serve. The gospel of Jesus Christ is the ultimate fulfilment of Genesis 21 – it offers good news of great joy to all nations, to anyone who would put their own faith in Jesus. What is our 1 story that we have for everyone in our life? It is this; the promised child Jesus brings eternal joy and laughter, and every person either belongs to Jesus’ line or they don’t. We want all those around us to come and deal with God in humility and faith. This is what Abimelek did and this is what God is doing through the witness of his people – offering his acceptance and blessing to the lost world.
Christ Church Riverside, let us leave this place changed today;
- With hearts that will deliberately delight because of baby that we have been given, the man who died on our place, the God who defeated death and walked out of the tomb
- With lives that steadfastly accept any scorn or opposition or division that comes our way because of the saviour who we have.
- With mouths ready to invite others to come to the guest services next week, to come and hear the gospel invite from the God who has made a way to offer eternal acceptance to anyone who would come in repentance and faith.
Intro: Big questions
- The promised child brings laughter (v1-7)
“Now the LORD was gracious to Sarah as he had said and the LORD did for Sarah what he had promised”
This is always how God acts;
- As he had said
- What he had promised
Abraham and Sarah always should have fully stood on the promises of God
With our eyes on the cross of Christ we must stand on the promises of God
- Are we people of gratitude and joy
- Should we not be laughing more?
- The promised line brings opposition and division (v8-21)
“Sarah saw that the son whom Hagar the Egyptian had borne to Abraham was mocking.”
- The promised child brings opposition
- A promised people brings division
The gospel is both the aroma of life and the aroma of death. Don’t be surprised.
- The promising God offers acceptance (v22-34)
“At that time Abimelek and Phicol the commander of his forces said to Abraham, ‘God is with you in everything you do.’”
- God is with you in everything you do
- Pray for the neighbours around us to see this in us
- We want to offer God’s acceptance to the world
Application: Hearts, lives and mouths
| Questions to think more about:
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| Memory verse: Genesis 21v1 “Now the LORD was gracious to Sarah as he had said and the LORD did for Sarah what he had promised.” |
| My own questions for later:
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