Trinity: This Changes Everything (John 17:20-26)

Introduction: Review

People have come up with all sorts of desperate sounding illustrations to explain the Trinity. You ask, “Explain why Bible teaches that the one God has always existed in three persons, the Father, the Son, and the Holy Spirit.” And some helpful soul will tell you, “Well, it’s like a three leaf clover, or (for you physicists and engineers) it’s like water that exists as ice, liquid, and steam. Or the Trinity is like an egg, which has a yolk, a white, and a shell, but is one egg.” And that’s a really compelling illustration, isn’t it? Our God is like a gigantic egg! It all sounds really bizarre. And the next question is this: how could the eggishness of God be anything more than some curiosity? What difference could this mystery possibly make to my life? And how could my heart ever be drawn out to a God like this?

But dear friends, as we’ve seen in this series, this isn’t at all how the Trinity is explained to us in the Bible. You never even see the Trinity put forward as a confusing puzzle, a conundrum. Rather, we have our God, Father, Son, and Spirit, put forward in the most wonderful, joyful, confident terms. It’s not presented to us as a question, but as the answer to our questions.

What is God like? Well, you could ask, before he created the universe, what was he doing? Jesus tells us here in John 17:24, "You loved Me before the foundation of the world" (John 17:24). The essence of God is his love, and the three continually pour out love to one another and receive love in return. God is a perfect community of self-giving and receiving, united in infinite being. And loving others isn’t a strange thing for God, because it’s at the center of who God is. So, here at last is the right place to start. Forget the egg! The Bible says, “God is love.”

Imagine a god who’s always been a single person, alone for all eternity. Obviously, god would not be a Father eternally delighting in his beloved Son. He could perhaps become a Father, but he wouldn’t be a Father. God could perhaps begin to love, but he wouldn’t be love. Love requires an object. In fact, you should ask whether such a god would even know what love is? Would he know what fellowship is? How could he? For that god could not from all eternity delight in the fellowship and love of another, nor could he be love. He would have no love to give, and no fellowship to share. He wouldn’t know how to love others. If god were not Trinity, you might end up with a god to fear and obey, but not to love as father. And you wouldn’t find your heart drawn out to him. But because he is a Trinity, God is delightful. God is a fountain of love; he is love, he could not not love. And you simply could not say that of any other god. And if God were a single person, that would not be true.

I point this out because we live in a day in which people want to erase distinctions. People say that all religions are the same, with different names for god, just like queso, formage, and ost are just different words for cheese. So it is with God. It’s just different names for the same thing, and all religions therefore are basically the same. But this is absurd. You simply can’t stuff the Father, Son, and Holy Spirit into anyone else’s thought of God.

In your notes, I’ve put a picture of another god that I hope won’t offend anyone, though we honor him all once a week and have a day in his honor. Does anyone recognize him? Maybe you kids? It’s Thor. Thor is one of the chief gods of the Vikings, rather cruel, and he likes to smack down people. Now if Thor is god, does it matter? Let me put it to you this way, if the over-sexed, beer sloshing, war-god of the Vikings is really god, you can hardly blame the Vikings for acting as they did. If Thor is god, you should be a Viking! And right after the service, we’ll go and be godly. We’ll go out and smack down some people, take some women, and drink beer.

The point is this: Who God is has everything to do with what it means to be godly, in other words, what it means to be like God. And being like another god would look very, very different. Consider the bloodthirsty god of the Aztecs who demanded child sacrifice. You see that God, and you’ll know why the Aztecs were such bloodthirsty conquerors and, for example, why their kings demanded games be played to the death in their presence. Or think about the hormonal outbursts of the gods of Greece and Rome, and you’ll learn something about why classical society often bordered on debauchery.

One of the earliest creation stories we have is the one from ancient Babylon called the Enuma Elish. In it, we learn why God created the world, and us in it. The god Marduk puts it bluntly. He creates mankind so that the gods can have slaves. Love for others is clearly not the heartbeat of Marduk. Of course, he’d probably love himself, but that’s not the point.

Now, friends, our God is a Trinity, an eternal community of love and joy. Surely, the God of the Bible isn’t like any other god. And the point today is that this changes everything. What would it be like if love and fellowship weren’t central to God’s being? If god were a single, solitary being, a hermit in all eternity, surely you can forget other people. If god were cruel and proud, you can be cruel and proud.

But here is our God, who doesn’t demand that we sacrifice our children to him, but who comes in love to sacrifice himself for us, while we were yet enemies. And so, it’s no wonder that the two great commandments are to love, to love God with all that’s in us and our neighbor as ourselves. For that is being like God, overflowing with love others. When you start with the Trinity, you find a godliness that’s very warm and attractive.

God says, “Be holy because I am holy.” And what does that mean? He goes on to say in that chapter, Leviticus 19, turn from idols and come before him with fellowship offerings. Have care for the poor, and forsake lying and stealing. Don’t hate your brother in your heart, but “you shall love your neighbor as yourself, I am the Lord” (Lev 19:17-19). This is the beauty of holiness. John writes this: "Beloved, let us love one another, for love is of God; and everyone who loves is born of God and knows God. He who does not love does not know God, for God is love" (1 John 4:7-8).

Now, someone will say, what about God’s wrath? Well, friends, more about this tonight, but where do you think the wrath comes from? It comes from his eternal love. One writer puts it this way, “If I could twiddle my thumbs and yawn while my daughters suffered, it would prove I didn’t really love them. … Love cares, and that means it cannot be indifferent to evil” (Michael Reeves, Delighting in the Trinity, p. 118). If you start with God as Trinity, it all comes together, but if you miss this, you miss everything, and mess up everything in your life. Augustine therefore wrote 1500 years ago in is book on the Trinity: “In no other subject is error more dangerous, or inquiry more laborious, or the discovery of truth more profitable” (Augustine, De Trinitate 1.3.5; cited in Kevin DeYoung, The Truth We Almost Forgot, p. 49). So, what I’d like to do with you this morning is to remind you why this changes everything. The Trinity determines everything in the Christian faith and life, of course. But I’ve selected five from this passage to illustrate it today.

1. The Christian Life

The most basic definition of what it means to be a Christian is given here. A Christian is someone who has come to dwell in God and God in us. We have been welcomed into the love, fellowship, and spiritual unity of God, Father, Son, and Spirit. Verse 21, "that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us" (John 17:21).

The most basic and important thing we can say about the Christian life is that it’s a life in God and God in us. This is taught repeatedly. John writes in his first letter, "God abides in us, and His love has been perfected in us. By this we know that we abide in Him, and He in us, because He has given us of His Spirit. … And we have known and believed the love that God has for us. God is love, and he who abides in love abides in God, and God in him” (1 John 4:12-16). Or a few chapters back, Jesus says, "If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our home with him” (John 14:23).

Christianity isn’t primarily a matter of what we believe, or what we do, or how we feel. It’s sharing the very life of God in us. It’s called a new birth, a new life, a new creation, Christ in you, the hope of glory (Col 1:27, John 3, 2 Cor 5:17). Galatians 2, "It is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me" (Gal 2:20).

And when we partake of his life, we partake of his love. Verse 26, “that the love you have for me may be in them, and I in them.” God gives his children his own love to share, and this makes us new from the inside out, now overflowing with love as God is overflowing with love. And this is why the great commandant is what it is: to love the Lord with all that’s in us, and then our neighbor as ourselves. You would never get that if you didn’t have a Trinity.

So life as a Christian involves having our hearts turned from lesser loves, and unworthy loves, and unsatisfying loves, especially the love of self, to the love God who is infinitely lovely, to find our hearts captivated and expanded and enriched with him. He is our treasure. It’s about having the love of God made complete in us, and then overflowing to others.

And here is the standard of our love: By this we know love, that Christ laid down his life for us—while we were yet sinners and enemies. Remember this when a brother or sister sins against you: your Father has sent his Son in love to cover your sins. And when our fellow Christians are hurtful to us, we’re likewise called to love them in such a way that no sacrifice is too great and no kindness is too extravagant. There’s much, more I could say. But the Trinity shapes everything about the Christian life, what it is and what it does.

2. The Good News

Jesus mentions twice in this passage about the good news going to the world: that world may believe that You, Father, sent me, and have loved them as you loved me.

Friends, what is the good news? And what does the Trinity have to do with it? Well, this changes everything. If, like in many religions, god from all eternity was just a solitary Lord, all about commanding, what would the gospel be? The gospel might be that he’s the ruler, we’ve broken the rules, but he maybe he’ll forgive us somehow; and we won’t be punished and may get some benefits, provided we remain under his rule.

Now, you might hear the gospel presented something like this. You’ve sinned. Jesus died for sinners. And if you accept that, you get forgiveness and eternal life. Now, if that’s the gospel, Jesus is basically just a cheap get-out-of-hell-free card. And it’s not like you’re enjoying God, or loving God, though you’d probably be grateful, like a policeman who let you off for speeding without writing a ticket. Thanks a lot, Jesus! You’d be grateful, but you wouldn’t love him. In fact, you’d probably just love yourself and just want to save your own skin, rather than the goal of it all which to know, love, and enjoy God our Father, Christ our Redeemer, the Spirit our comforter. If you don’t desire him, you’re thinking of a different God. You’re confusing him with someone else.

It’s very interesting, by the way, to listen to the new atheists describe the kind of god that they don’t believe in. They invariably describe some other God besides the Trinity, a good that’s not good news at all. They describe a god who’s a remote, commanding, a cold judge, a kind of slave-master. It’s like the prodigal son’s older brother said to his father, “Look, all these years I’ve been slaving for you” (NIV). That’s the idea a lot of people have. And they import that into Christianity. They think that the God of the Bible is just a heartless dictator, and they don’t want God to exist. And I agree. If God is not love, if God is dictator, I don’t want God to exist either. It’s not good news.

But our God, it’s totally different. The good news is not that we can merely be forgiven and come back as servants under the reign of the eternal dictator. What do you read here? God the Father embraces us with the love that he has for his own Son. Verse 26, "I’ve declared to them Your name … that the love with which You loved Me may be in them, and I in them" (John 17:26). This is what we also proclaim. We proclaim God as Father who will embrace all who come to him in his son with the very same love. We proclaim Christ as Lord, the Lord who’s come to serve his people and lay down his life for them. We proclaim the Spirit who gives life from the dead and brings us into communion with God, so that all that’s Christ’s is ours and we cry out, “Abba, Father.” This is a far richer God, and therefore a far richer gospel.

End of Verse 23, “You have loved them as you have loved me.” You are as loved as Jesus. Does any other religion or philosophy offer you anything remotely as good as that? One writer puts it this way: "[The] good news of salvation is that God, who in himself is eternally the Father, the Son, and the Holy Spirit, has become for us the adoptive Father, the incarnate Son, and the outpoured Holy Spirit. God the Father sent the Son to do something for us and the Spirit to be something in us, to bring us into the family life of God" (165).

Jesus uses the most tender and affectionate language to describe his relationship with his Father in heaven. He dwells eternally, it says, in the bosom of the Father (John 1:18). And that is where we are being brought. We’re redeemed not merely as creatures or slaves but as children, to enjoy the limitless love and glory that the Son has always known.

3. Prayer

This context, of course, is a prayer. And Prayer is a Trinitarian experience. To begin, Jesus teaches us to pray to our Father, and to remember that he knows, and cares, and delights to give good gifts to his children. What other god has prayers like that, I ask you. And you’ll notice that prayer and praise in the Bible is almost exclusively directed to God. I know that some are in the habit of regular prayer to Jesus, but that’s not the Biblical pattern or teaching. There are a small handful of prayers to Jesus in the Bible, and none to the Spirit. But Jesus himself rather directs us to come with him as dearly loved children in praying, “Our Father.”

And as our Mediator, Jesus brings us to the Father as our father also, sharing in all the privileges of Christ. And we read the Spirit of adoption enables us to cry, “Abba, Father,” from the heart, testifying to us that we are the children of God. So by the Spirit we cry what the Son himself has always cried as we come to our Father as his beloved children. And this is how prayer is a Trinitarian experience. The Spirit is the wind in our sails, Christ our mediator enabling us to approach God as our Father just as he always has.

And so we don’t pray as the irrelevant servants of a distant God. We’ve been carried on the heart of Jesus, our High Priest before our Father in heaven. And the Spirit of God within us cries, “Father.”

You see what the Trinity has to do with prayer? The triune nature of our God is not an encumbrance on Christianity but the very undergirding truth that makes it good, lovely, and beautiful. This isn’t some airy, impractical truth. It’s something we can revel in every time we pray. Instead of nervously calling, "O Distant Creator," we can pray "Our Dear Father," enjoying the Son's own relationship and privileges. And we can do so with the Son's own boldness, secure in him and enabled as he is by the Spirit. The father loves us as he loves the son. That’s why we pray. And that’s why we pray boldly.

4. The Church

More than once, the Bible joins the life of the church to the triune life of God. Here it is in our passage a few times, such as verse 21, “that they may be one, Father, just as you are in me and I am in you.” These words remind us how we are together to enjoy the same love and unity. And this is not just an invisible, spiritual unity, you notice, but one that the world can see, “that the world may believe that you have sent me.” The world will see the church demonstrating the redeeming, healing power of love and be ravished by our God, brought to believe in Christ.

The harmony of mankind has been shattered by sin and everywhere today there are walls of hostility, broken homes, divided communities, separation between rich and poor, red and yellow, black and white. The Lord will have his church be a visible alternative, a counter-culture, a place where the dividing walls have been trampled down in his love. Here a new race of people based not on flesh but spirit. Here is a new society, governed not from earth but from heaven. Here is the city of God where we dwell together secure in the love of God and each other.

The very fact that we were made in God’s image means that we were made for fellowship. There has always been an affectionate social life within God. And what do you think the church is supposed to be therefore? Jesus chose twelve disciples to be with him (Mark 3:14).

More and more today, people try to find fulfillment in independence, not committing to relationships. People are delaying or forsaking marriage, and slow to commit to a church, and often change friends every couple years. Relationships are casual and open-ended. People don’t consider the value of family ties when choosing a job or place to live, and so forth. We have shallower and fewer relationships. But this is contrary to the fact that we’ve been created in the image of God. What does is mean for the Son to have a Father, and the Father to have a Son, the Son of his love, in whom he delights and pours out love into heart by that Holy Spirit.

As we saw in a previous study, God created man male and female for this reason, brining them together in marriage, where each is to know and share the love, security, and delight that nothing but death can separate, for better, for worse, for richer, for poorer.

And in the family, as in the church, we’re to enjoy Philadelphia, brotherly love, and storge, family affection.

Heaven itself is not described as a harem of virgins or a beautiful wilderness, but as the city of God (Rev 21:2, 10). Nor should we now as Christians long to live lives that are detached, disinterested, and self-consumed. We’re called to warm the community with the love of God we’ve received.

We’re to be united in fellowship, just as God is united in loving fellowship. You may have heard the Greek word for this, which is koinonia, which also means sharing, communion, having in common. So in John 17:20, "all Mine are Yours, and Yours are Mine" (John 17:10).

In the same way, we share the work of ministry, of giving and receiving (Phil 4:15-16), so that no one has need (Acts 4:34-36), of using our gifts for each other’s good (1 Cor 12:7), bearing one another’s burdens (Gal 6:2), weeping with those who weep, rejoicing with those who rejoice (Rom 12). We share in the work of ministry to the world, calling people to be reconciled to God and share in our joy (Phil 1:5).

All of this is brought out in the Lord’s supper, which is called the communion, or participation, in the body of Christ, by the body of Christ (1 Cor 10:16). This doesn’t mean that we only commune in the sacrament. But the Lord’s Supper is the solemn spiritual festival that binds us together to him in that new covenant in his blood. And wherever we go, we are the Lord’s, communing in his body and blood, receiving the blessings and benefits of his death and new life.

And when we receive the bread from an ordinary fellow-believer and pass it on to the next, it expresses the truth that the church is a fellowship of giving and receiving, in which God’s gift is shared among us, in which we all have something to give and something to receive. Imagine that someone wouldn’t give, that the plate came to them and stopped. Part of the church would suffer. And so it is in our common ministry.

5. Assurance

What about our assurance? If God’s just the heavenly Lord and we his servants, why wouldn’t he cast us off if we offend him? Would assurance be possible? But we have something radically different. The spirit unites us to His Son, so that we’re in Christ Jesus. And therefore we’re children of God. Now, the Father could never weaken or cool in his love for his son, let alone send him away. And if we’re embraced by the eternal love of the father, Christians are perfectly safe in the Son, who promises that none will ever be snatched out of his or his father’s hand.

Sinclair Ferguson illustrates this well when he says, “I’ve often reflected on the rather obvious thought that when his disciples were about to have the world collapse in on them, our Lord spent so much time [here] in the Upper Room speaking to them about the … Trinity. If anything could underline the necessity of Trinitarianism for practical Christianity, that must surely be it!”

The Trinity comforts us in our sorrow. When Jesus told his disciples he was going away and their hearts were troubled, the comfort he brings is through this doctrine of the Trinity, “Do you believe that I am in the Father and the Father is in me?” (John 14:10), “But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, he will bear witness about me,” (John 15:26), and “Nevertheless, I tell you the truth: it is to your advantage that I go away, for if I do not go away, the Helper will not come to you. But if I go, I will send him to you” (John 16:7).

Paul writes, “Your life is hidden with Christ in God" (Col 3:3). Nothing can separate you from the love of God, who is our shield, our mighty fortress, our hiding place (Ps 84:11, 18:2, 32:7).


Single-person gods must, by definition, have spent eternity in absolute solitude. Before creation, having no other persons with whom they could commune, they must have been entirely alone. Love for others, then, cannot go very deep in them if they can go for eternity without it. And so, not being essentially loving, such gods are inevitably less than lovely. They may demand our worship, but they cannot win our hearts.

What’s your Christian life like? What’s the shape of your faith, your gospel? It all depends upon what your God is like.

The basic problem in the world is not that we’ve strayed from being law-abiding people but that we’ve strayed from him. And what is redemption, but to be brought back as his beloved children. What is the Christian life about? What are our churches like, our marriages, our relationships, our mission? It’s all a reflection of the way that we think about God.

And so Jesus says that He is the way. We must begin with a God who has a beloved Son, a Father and Son of eternal love in the fellowship and communion of the Spirit. Without Jesus, we can’t know God as a loving Father. Without Jesus, we can’t know him as our loving Father.