How Can I Reach My Unbelieving Spouse with the Gospel?
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How Can I Reach My Unbelieving Spouse with the Gospel?

What Is the Trinity? {Lord’s Day 8}

This article is part of our weekly series, “Our Life’s Comfort: One Year of Being Shaped by the Scriptures.” Read more from the series here.

(24) Q. How are these articles divided?
A. Into three parts: God the Father and our creation; God the Son and our deliverance; and God the Holy Spirit and our sanctification.



(25) Q. Since there is only one divine being,why do you speak of three: Father, Son, and Holy Spirit?
A. Because that is how God has revealed himself in his Word:these three distinct persons are one, true, eternal God.

The eighteenth century German philosopher Immanuel Kant said, “Absolutely nothing worthwhile for the practical life can be made out of the doctrine of the Trinity.”[i] Was he right? Is the Trinity simply a theological secret handshake that proves one’s orthodoxy? More personally, if you affirm the historic, orthodox doctrine of the Trinity, does it matter to you? Do you rejoice in the unity and diversity of the Godhead? Do you pray in the Trinity, not simply as a “formula to follow” but as “the natural movement of a mind instructed in gospel truth and a heart enflamed by gospel grace”?[ii]

The Apostles’ Creed handily summarizes the entire Christian faith using the scheme of the Trinity. But more basically it helps believers declare their total dependence on the Triune God. Let’s learn from the Creed to affirm the Trinity. More than that, let’s be captivated by what has energized and united Christians from the start: our God is one divine being in three distinct persons.

What Is the Trinity?

This question is ultimately answered not by creeds, councils, or kings, but by the Bible. God used churchmen to clarify what the Bible says, usually in response to false teaching. But the church didn’t invent the Trinity. We speak of God in three persons “because that is how God has revealed himself in his word.” Here’s what we learn from the Bible. “The Father is God, the Son is God, the Holy Spirit is God. Yet there are not three gods; there is but one God.”[iii]

The Israelites, much like us today, were embedded in religiously pluralistic societies like Egypt, Canaan, and Babylon. Every group had their god or gods—inferior knockoffs of the one true God. So it makes sense that the most basic and well known confession of faith in the Old Testament is the Shema: “Hear, O Israel: The Lord our God, the Lord is one. You shall love the Lord your God with all your heart and with all your soul and with all your might” (Deut. 6:4–5). There is one God. Yet this one God exists in three persons. The Son is not the Father, but is sent by the Father (John 17:18), reveals the Father (14:9), and is the way to the Father (14:6). The Spirit is not the son but carries on his work in the world during his physical absence (14:16, 17). The three persons act distinctly from, though in harmony with, each other and commune with each other as at Jesus’ baptism (Matt. 3:16–17).

If you learn the theme of “one God in three persons,” you see it everywhere in Scripture. Here are just two examples. Paul instructed the pagan Philippian jailer so that he gave up trusting in the pantheon of his father’s gods and “believed in God” (Acts 16:34), the one true God “who made the world and everything in it, being Lord of heaven and earth” (17:24). But when he and his family received the sign of the covenant (33)—marking them as God’s people—they were baptized “in the name of the Father and of the Son and of the Holy Spirit” (Matt. 28:19).

Peter greets all believers with grace and peace “according to the foreknowledge of God the Father, in the sanctification of the Spirit, for obedience to Jesus Christ and for sprinkling with his blood” (1 Peter 1:2). Paul makes a similar pronouncement: “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). The Aaronic benediction of the Triune God (Num. 6:24–26) becomes explicitly Trinitarian following the revelation of Jesus and the outpouring of the Holy Spirit.

The Trinity is not fanciful theological mathematics; it is plain and plentiful biblical revelation of who God is.

How Important Is Trinitarian Theology?

In other words, is the Apostles’ Creed—the most important summary of the Christian faith—right to organize theology around the three persons of the Trinity?

The Trinity is basic Christian doctrine. “Now this is the catholic (universally Christian) faith: that we worship one God in Trinity and the Trinity in unity.”[iv] In a pinch the confession of a true believer could be shortened to the creed’s first four words: “I believe in God.” But believers unpack that statement by identifying the one true God as Father, Son, and Holy Spirit; our creator, redeemer, and sanctifier. When we confess the historic Christian faith using the Apostles’ Creed, we aren’t emphasizing our faith; the three-fold repetition of “I believe” isn’t a pat on the back. It is a signal to our desperation and the sufficiency of the triune God to perfectly answer our needs. Sound theology depends on the doctrine of the Trinity. “The truth is that one cannot preach Jesus even in the simplest terms without preaching him as the Son. His revelation of God is the revelation of ‘an only begotten from the Father,’ and you cannot preach him without speaking of the Father and the Son.”[v]

And the Triune being of God helps us adore both the specialized work of the three persons and the unity of the Godhead. In a beautifully compact message of divine grace, Peter emphasized a special act of each of the divine persons. The Father elects, the Son offers himself as the redemption for sinners through his shed blood, and the Spirit sanctifies—he makes God’s people holy by giving them everything earned for them by Jesus’ obedience (1 Peter 1:2). But the three persons do not work in isolation; the works of the Trinity are indivisible. As the Triune God said, “Let us make man in our image” (Gen. 1:26), so the Triune God chose some people for salvation. It was Jesus who “who gave himself for our sins to deliver us from the present evil age.” But he did so “according to the will of our God and Father” (Gal. 1:4). The Spirit sanctifies us. Yet Paul can say, “Now may the God of peace himself sanctify you completely” (1 Thess. 5:23).

So is the Trinity practical? The question isn’t really right. It betrays a utilitarianism distasteful to the topic. It is like asking if your best friend is useful, or what material advantages love has. The Trinity is. The Trinity is love. The Trinity is joy. The Trinity is wisdom. The Trinity is goodness. And, of course, there are hosts of benefits from knowing God. But let’s not allow “the triune God in eternity [to be] swallowed up by who we want him to be for us in history.”[vi] All theology is summed up in this one point: the Triune God saves sinners. By faith you can know and love—and know that you are known and loved by—God the Father, God the Son, and God the Holy Spirit. No truth is more important.

[i] Klooster, Our Only Comfort, 256.

[ii] Pat Quinn, Praying in Public: A Guidebook for Prayer in Corporate Worship (Wheaton, IL.: Crossway, 2021), 46.

[iii] Athanasian Creed, 15–16.

[iv] Athanasian Creed, 3.

[v] Leslie Newbigin, in Klooster, Our Only Comfort, 247.

[vi] Matthew Barrett, Simply Trinity: The Unmanipulated Father, Son, and Spirit (Grand Rapids: Baker, 2021),31.

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William Boekestein

William Boekestein is the pastor of Immanuel Fellowship Church in Kalamazoo, Michigan. He has written several books and numerous articles. He and his wife, Amy, have four children.