Knowing the Triune God (LD 8, q&a 24-25)


“I believe in God.” Many people say that. They believe that there is something, someone greater than they, who is in charge of their life and must be worshiped. But who is this God? What is he like? What is my relationship to him? What does he want of me?

“I believe in God.” But how can we know him? Can we even get to know him? If he is not from this world, but belongs to a higher dimension (as it were), can we understand anything about him? Where would we look?

As we begin our study of the Apostles’ Creed, it is good to think about that question. If we say “I believe in God,” who do we believe in, and how can we know? The Heidelberg Catechism doesn’t spend too much time on this question, but focuses in on one aspect of the Apostles’ Creed: How come you talk about the Father, the Son, and the Holy Spirit, even though there is only one God? We will get to that question, but first we discuss more generally where our knowledge about God comes from.

    Knowing the Triune God.

        1. Revealed in his Word
        2. Father, Son, and Spirit
        3. The one true God

Revealed in his Word

God made the world in which we live. As a result, you might say, his fingerprints are all over it. The poet of Psalm 8:3 is amazed: “When I look at your heavens, the work of your fingers, the moon and the stars, which your have set in place…!” Psalm 19:1 sings that “the heavens declare the glory of God, and the sky above proclaims his handiwork.” Psalm 104:24 is a prayer of praise: “O LORD, how manifold are your works! In wisdom you have made them all.” We can learn something about God from the things he has made. The apostle Paul says that God’s “invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, even since the creation of the world, in the things that have been made.” (Rom. 1:20)

If you go to an art exhibit, the paintings or sculptures tell you something about the artist. You may get a sense of her personality and outlook on life. But you can’t really say that you now know the artist. You would have to meet her and have a conversation to really know her. It is the same with God: the world he made tells you a thing or two about him, but it cannot help you to really know him.

Because God is spirit, not made of the stuff of this world, invisible, we cannot see directly who he is. The only way we can really know God is when he reveals himself to us. When he comes into our lives and deliberately shows what he is like. In particular, God speaks about himself. Throughout history he told us what we needed to know.

As believers in God, we must therefore hear and accept all that God has revealed to us in his Word (q&a 21). That is how we get to know what he is like. The stories, prophecies, psalms, and other parts of the Bible paint us a vivid portrait of God and his activities. We learn that he is great, almighty, powerful, all-knowing, wise, just, gracious, merciful, compassionate, and so on. Now when we look at the moon and stars we not merely see the suggestion that there is a greater power, but we recognize that this is the work of a good and merciful God, who cares for people and has a plan of salvation.

Believers study God’s revealed Word to get to know him well. The church treasures these words and proclaims them to the world. When the people in Athens had an altar “to the unknown god” (Acts 17:23), Paul said: “What you worship as unknown, this I proclaim to you.” In the same way, when we meet people who feel there must be “something” out there, we tell them eagerly about God as we know him. That is what the church has done throughout the ages: receiving the self-revelation of God, learning from it everything that we can know about him, and passing on that knowledge to others.

Father, Son, and Spirit

When you listen to Christian believers telling about their God, you hear them speak not just about “God”, but about “the Father” and “the Son” and “the Holy Spirit”. It may make you wonder: are those three different persons? Does that mean that there are really three Gods? How does that work? Since there is only one God, why do you speak of three persons, Father, Son, and Holy Spirit?

To answer that question, we may be tempted to give a clever argument why there should be three persons in God. We might try to give some philosophical reasoning as to why he would be like that. But there is only one answer that works, one answer that counts. The catechism gives that answer (q&a 25) when it says: Because God has so revealed himself in his Word. God says so, and therefore it must be true. There is no other way to know anything in detail about God, except by reading and listening to what he reveals. And God reveals himself as one God, but also as Father, Son, and Holy Spirit.

We call this the doctrine of the Trinity, from the Latin word for “three”. As the hymn says: “God in three Persons, blessed Trinity.” The word “Trinity” does not occur in the Bible. There is no direct statement about God being “three Persons”. (Some Bible versions have something like it in 1 John 5:7: “For there are three that testify in heaven: the Father, the Word, and the Holy Spirit; and these three are one.” But it is almost certain that this text was added at the end of the Middle Ages, and was not part of the original Bible text.)

Still, the Trinity is clearly revealed in the Bible. Sometimes the three divine persons are listed together. “Baptize them in the name of the Father, the Son, and the Holy Spirit,” said Jesus to his disciples (Mat. 28:19). Paul wrote: “The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all.” (2 Cor. 13:14) In Eph. 1:17, Paul prays “that the God of our Lord Jesus Christ, the Father of glory, may give you the Spirit of wisdom.”

Doesn’t that mean that we now have three persons who are God? God the Father, God the Son, and God the Holy Spirit? People have tried to avoid this conclusion in two ways.

Some have denied that Jesus Christ is really God. Yes, they would say, he is a very special creature of God, perfectly reflecting the glory of God, very similar to God—but not actually himself God. In the ancient church, Arius and his followers took this approach; their views were quite popular for some time. Today we find this view in so-called Unitarian churches, and among Jehovah’s Witnesses.

But, as we saw earlier in the catechism, it is essential that our Saviour is truly God; and the Bible gives Jesus Christ the same titles and glory as God the Father. Think for instance of the beginning of the gospel of John: “The Word was God”; or Thomas’s confession: “My Lord and my God!” (John 20:28) The church affirmed this clearly in the year 325, at the council of Nicaea, when it said that Jesus Christ is “true God of true God” and “of one substance with the Father.”

In the same way, some denied that the Holy Spirit is a divine person. They thought of the Spirit more as the impersonal power of God. But here, too, the church insisted that the Holy Spirit is a divine person. The council of Constantinople (381) added to the Nicene Creed the statement: “And I believe in the Holy Spirit, who is Lord and giver of life… Who is worshipped together with the Father and the Son.”

Another attempt to avoid the idea of three divine persons involves thinking of Father, Son, and Spirit as different manifestations of the same person. You find this, for instance, in the so-called Oneness Pentecostal churches. They would say that Jesus is the truly divine person, and that he embodies both the Father and the Spirit. Oneness Pentecostals therefore baptize people in the name of Jesus only.

But the Bible presents Father, Son, and Holy Spirit as different persons, different actors. Jesus prayed to the Father. The Father sent the Holy Spirit, who is called “another comforter”, different from Jesus.

If we are serious about knowing God he has revealed himself in his Word, we must insist that there are three distinct persons, the Father, the Son, and the Holy Spirit.

The one true God

And yet we do not say that there are three Gods. We respect the clear teaching of the Bible that “the LORD our God, the LORD is one.” (Deut. 6:4) There is only one God. That was not only the Old Testament situation, the heart of Israel’s faith. Jesus himself affirmed it; nothing has changed between the Old and New Testament!

And this one God is one. That is, he is not internally divided. He is united in all that he does. He has one plan, one purpose. He is constant; he does not change. He is Yahweh, “I am who I am, I will be who I will be”.

This oneness of God is of the utmost importance for our faith. Pagans often believe in multiple gods, who can be at odds with each other; and worship becomes akin to hoping that you pick the winning team, that you find the favour of the god who happens to win. Or they believe in a god who is whimsical, who does not care about people or does random things. You cannot rely on such a deity.

As Cristians, we find hope in the fact that God is one, and constant, and unchanging. “I, the LORD, do not change. Therefore you, children of Jacob, are not consumed.” (Mal. 3:6) “The steadfast love of the LORD never ceases; his mercies never come to an end; they are new every morning: great is your faithfulness!” (Lam. 3:22-23) There is one true and eternal God.

But how does that fit with the three persons, Father, Son, and Holy Spirit? We must conclude that even though they are  three distinct persons, they are nonetheless one. They are so united in their being, in their purpose, and in their activity that we can truly say: they are one God. In his ministry, Jesus confirmed this. “I and the Father are one,” he said (John 10:30). “If you see me, you have seen the Father.” (John 14:9

What does this mean practically? Our forefathers concluded: “the works of the Trinity on the outside are indivisible.” When we see God at work in the world, in creation and in salvation, there is no division or opposition. Father, Son, and Spirit work together to accomplish the same purpose.

If you listen carefully to the Bible’s account of the creation of the world, you see the Trinity at work, together. God the Father taking the initiative. Speaking the divine Word, whom we now know as the Son of God, the Word who became flesh. And the Spirit of God hovering over the waters, producing life everywhere.

If you listen carefully to the Bible’s account of our salvation, you see the Trinity at work. God the Father sending the Son into the World. The Son taking on human identity, becoming one of us. The Holy Spirit, empowering the Son, and breathing new life in all who belong to him, giving them faith and holiness of life.

If you think carefully about your Christian life today, you recognize the Trinity at work. God the Father governing you, powerfully guiding your life in loving care. God the Son, seated at the right hand, as your King and as the example to follow, Mediator between God and man, founder and perfecter of our faith. God the Holy Spirit, filling you and filling the church with worship and power, with joy and celebration, teaching you to live the Kingdom life.

In all this work, the three Persons are as one, working to bring the world to its completion, to a future where sinners saved by grace will be perfect worshippers, joining in intimate fellowship with their Triune God and Saviour.


God has revealed himself in his Word, making clear that the three distinct persons, Father, Son, and Holy Spirit, are the one true and eternal God. Logically, we cannot make the Trinity “fit” perfectly. That is not a bad thing. If we could comprehend the depths of God, would he still be God? Shouldn’t God be too great for our finite minds, by definition?

The Trinity shows us the abundance and generosity of who God is. He is so great that he can only be described as three. Within God himself are the most profound relationships, most notably the love of the Father for the Son, and of the Son for the Father. The gospel gives us a little glimpse into this divine life. It is marvellous. And this one God, who is too great to be captured in just one person, is for us. He allows us to share in the fullness of his life.

We can know God, only because he reveals himself in his Word. But what a revelation it is! The Father, who speaks from beyond this world; the Son, who as God’s incarnate Word has revealed God in our own humanity; and the Spirit, who reveals God within us and among us. We may not understand all of it, but we certainly confess it with gratitude and joy.


Reading/listening questions

  1. Can you get to know God by studying the world he made?
  2. Why do we speak of God as “Father”, “Son”, and “Holy Spirit”?
  3. List two Bible texts that are clearly “Trinitarian”.
  4. Why is it important that we believe that God is one?
  5. Describe the roles of Father, Son, and Holy Spirit in the work of salvation.

Discussion questions

  1. Is the doctrine of the Trinity taught in the Bible, or is it a later invention of the church?
  2. The Athanasian Creed says in art. 2 about the doctrine of the Trinity: “Unless a man keeps it in its entirety inviolate, he will assuredly perish eternally.” And art. 28: “So he who desires to be saved should think thus of the Trinity.” Is believing in the Trinity that important?

Suggested Bible reading schedule

MondayJohn 1:1-5. What was the role of God the Son in the work of creation?
TuesdayMatthew 1:18-25. Was the birth of Jesus a Trinitarian work?
WednesdayJohn 16:12-15; John 14:15-17. What does this passage teach about “intra-Triniarian” relationships?
ThursdayGalatians 4:1-7. What role do Father, Son, and Spirit have here?
Friday1 John 4:7-21. How is this passage Trinitarian?
SaturdayRevelation 1:4-7. Explore the Trinitarian nature of this greeting.

Further reading

Speaking of the Trinity

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