A Profound MysteryHow the Trinity Helps in Our Evangelism

Here’s a piece I wrote for the FIEC publication called Primer. It’s available in the November 2019 print edition (full issue, free!). David Shaw provided some excellent editing for me that made the article much clearer, and the magazine layout is nice. So I’m providing the text here below for easy online reading, but the PDF of the article is better (link here and at download button below).

A Profound Mystery: How the Trinity Helps in Our Evangelism

Most people think that the Trinity will complicate evangelism. On this view, sharing the gospel is easy but explaining the Trinity is hard. The presupposition behind this common-sense view seems to be that evangelism is a straightforward thing, but the Trinity causes problems. But if you consider the nature of evangelism for a moment, it turns out that it is already a nested set of mysteries in itself. And those mysteries of evangelism can only be sorted out and understood with the help of the doctrine of the Trinity.  How does a person become a Christian? How can a few sentences in a human conversation bring about salvation, and launch a person on an endless journey into the life of God? All of these mysteries of evangelism lead toward, and culminate in, the mystery of the Trinity. It turns out, in other words, that evangelism is a mystery solved by the Trinity. This article considers the various ways the mysteries of evangelism already have the Trinity lurking within them, because evangelism is inescapably trinitarian.

I. Mystery of Scale

One mystery that may loom especially large for any evangelist is the surprising contrast between the brief message and the big result. Or (to put the contrast another way) how few words we say when sharing the gospel, versus how vast the reality of salvation is. This mystery is a kind of discrepancy of scale: how can a handful of words bring somebody into contact with the personal reality of God’s salvation? Already in the New Testament we see striking examples of this contrast. When Matthew tells us (Matt 3:2) that Jesus preached “Repent, for the kingdom of heaven has come near,” that very brief message is probably a shorthand summary for Jesus’ full message, as expanded in the Sermon on the Mount. Still, it is a strikingly short formula: a nine-word command for response to God’s decisive action. When the jailer in Philippi asks Paul, “what must I do to be saved?” he responds with a handful of words: “Believe in the Lord Jesus, and you will be saved—you and your household.” Again, these thirteen words reported in Acts 16 are a condensed, introductory summary of the whole message. We are told immediately that Paul and Silas went on and “spoke the word of the Lord to him and to all the others in his house.”

Perhaps the most striking New Testament example of a short message producing an outsized evangelistic result is Peter’s speech in Acts 10, in the house of Cornelius. “You know the message God sent to the people of Israel,” Peter tells these Gentiles. He goes on for a couple of hundred words (about ten verses), explaining clearly how God was “announcing the good news of peace through Jesus Christ,” describing the key points in life and work of Jesus Christ. His story falls very much into the pattern of the second article of the Apostles’ Creed. He concludes that “everyone who believes in him receives forgiveness of sins through his name.” But perhaps “concludes” is not the right word, because Luke tells us that “While Peter was still speaking these words, the Holy Spirit came on all who heard the message.” Surely this is among the greatest interrupted sermons of all time. Something massive broke out there in the house of Cornelius, triggered by Peter’s clear account of the saving life of Christ. We can anticipate the trinitarian aspect of this evangelistic event by saying that when Peter testified about the Son of God, the Spirit of God bore witness to the truth and reality of what he said. The Spirit bore witness to Christ, and salvation came to the house of Cornelius. The persons of the Trinity were in that room. The Spirit made Christ present; though the Son was exalted to the right hand of the Father, he was present in power where salvation was offered in his name.

Anybody who has proclaimed the gospel and seen people respond to it will recognize this pattern. No matter how competently the good news is set forth, the words spoken still amount to a mere handful. The response, when a listener experiences salvation, simply seems all out of proportion. The reason, of course, is that counting words is not the right way to measure spiritual communication. While God consents for his message to be carried along on faithful words (the pattern of which he himself provides  by inspiration), that message is not ultimately about the words, but about a spiritual reality. Evangelism is a verbal expression of a more-than-verbal reality, testifying to the presence of something, or rather of someone, who is truly there. The knowledge communicated through evangelism is knowledge by acquaintance rather than knowledge by description. That is why it doesn’t have to be an account that is proportionate to the result. Evangelistic words are pointers that indicate, or pick out, the Son by the power of the Spirit.

II. Mystery of Depth

This brings us to a second mystery, which is not a contrast of scale but of depth. Anyone communicating the gospel will necessarily pick out for presentation a few key elements of the message. A wise communicator will select, if possible, truths which are both central to the faith and also well suited for an introduction. What is amazing about proclaiming the Christian message is the way the simple truths, which can be explained and understood briefly by way of introduction, are so immediately connected to the deep truths which nobody will ever get to the bottom of or outgrow. Not many fields of knowledge are like this: we learn to cook by boiling eggs and toasting bread, but move on to advanced techniques and different ingredients. We learn to repair mechanical things by starting on simple machines and moving upward in complexity. The subject matter of geometry expands materially from first principles (point and line and plane) by developing more and more operations; the first pages of a geometry book are almost too simple, but skip forward twenty pages and the complexity is striking. But the Christian message introduces the reality of God the Father sending his Son and his Spirit to atone for our sins and bring us into fellowship, and further pondering of the Christian message only takes inquirers further into these same truths. We might say of salvation what Gregory the Great said about the Bible, that a lamb can wade in it while an elephant can swim.

Again, as with the mystery of scale and proportion, the explanation of this mystery is that the things we come into contact with at the beginning of the Christian life are not simply things (propositions, principles, claims), but spiritual realities. They are ultimately divine persons, the Son and the Spirit sent for our salvation by God the Father. We meet them in the message of salvation and never outgrow them in our spiritual development, because they are, in person, the good news of God’s salvation. What we receive, as Paul says in 1 Corinthians 2, is “the Spirit who is from God, so that we may understand what God has freely given us.” Notice that the gift of salvation has layers; it is a kind of double gift that includes something given (“what God has freely given us”), and something further given to increase our knowledge of what was given (“the Spirit who is from God, so that we may understand”). This is the spiritual wisdom imparted in salvation, and in explaining it, Paul reaches for trinitarian categories: God the Father gives believers both his Spirit, who searches all things (1 Cor 2:10-12) and knowledge of the mind of the Lord by way of the mind of Christ (1Cor 2:16).

Here we see the trinitarian reality underlying any person coming to faith. The God of the Christian faith is triune; Father, Son, and Spirit. But the structure of Christian faith itself is trinitarian, mediated in us by the light of Christ and the witness of the Spirit. And that means that our way of understanding is correspondingly threefold, as we grow by coming to greater knowledge of the Father through the mind of Christ and the searching of the Spirit.

A responsible evangelist will carefully select which parts of the total Christian message to communicate first, just as any communicator on any subject would. In fact, the actual doctrine of the Trinity (three persons in one being, how they are related to each other, and so on) might not be among the first topics to be broached. But the mystery of trinitarian depth means that in evangelism there is a peculiar kind of levelling effect, wherein the first truths are also the final truths. The most seasoned and profound spiritual thinkers will admit that they are only sinking deeper into the very realities that they encountered when they first believed. J.I. Packer put the point this way, after having explained salvation at some length: “Christ is what he is to believers … irrespective of how much or how little of this multiple relationship they have with him is clear to their minds.” And he recognized the similarity between the profoundest thinker and the new believer:

An apostolic theologian like Paul, for instance, had it all far clearer in his mind than did the penitent thief of Luke 23:39 43; yet Jesus’ saving ministry was as rich to the one as to the other, and we may be sure that at this very moment the two of them, the apostle and the bandit, are together before the throne, their differences in theological expertise on earth making no difference whatsoever to their enjoyment of Christ in heaven.[1] 

The Puritans distinguished between union and communion: union with Christ was an underlying reality that was the same for all Christians; while communion was an experience of fellowship that varied among believers and even throughout the course of one’s life. “Union is the foundation of communion,” said Richard Sibbes.[2] Communion arises from union, and seeks a fuller realization of it. The mystery of depth lies here, in the way that even the greatest spiritual growth consists in greater realization, experience, and understanding of, the union all believers share in the Trinity. All believers have, by nature, union with the Trinity; through spiritual experience and theological growth we cultivate communion with the Trinity.

III. Mystery of Agency

These mysteries of scale and depth bring us to the third mystery, which is a mystery of agency. When we are astonished that the human action of evangelism can bring about the divine result of salvation, we are registering the fact that the human action of evangelism is not the whole story. The words in which the gospel is communicated are human words with divine testimony in them, and the divine testimony is what is doing the work. The great Reformed theologian Zacharius Ursinus pointed out that since “conversion is the gift of God alone,” it would be madness “to attribute this conversion to the efficacy of man’s voice.”[3] And yet it pleases God to bring about conversion by the “foolishness of preaching,” a phrase in which Ursinus seems to hear the radical disproportion between human words and divine effects in evangelism.

When the New Testament underscores this mystery of agency, it tends to break into trinitarian terms and patterns. Consider Luke 10, when the disciples report to Jesus that some towns have accepted his message while others have not:

At that time Jesus, full of joy through the Holy Spirit, said, “I praise you, Father, Lord of heaven and earth, because you have hidden these things from the wise and learned, and revealed them to little children. Yes, Father, for this is what you were pleased to do. All things have been committed to me by my Father. No one knows who the Son is except the Father, and no one knows who the Father is except the Son and those to whom the Son chooses to reveal him.”

Jesus the Son, rejoicing in the Holy Spirit, thanks the Father for sovereignly revealing his truth to the simple while concealing it from the learned. As Jesus goes on to say, the knowledge of God is something locked up inside of God himself, and only by revelation is it made known to human persons. But Jesus puts this in interpersonal terms, saying not simply that “God knows himself,” but that the Son knows the Father, and the Father knows the Son. The only way into this closed circle of divine knowledge is by the Son’s revelation of the Father. In another place, Jesus not only points to his Father as the one who reveals, but explicitly contrasts the Father’s work with human agency: “this was not revealed to you by flesh and blood, but by my Father in heaven.” (Matt 16:17)

IV. The Mystery Beneath the Mysteries

These lesser mysteries of evangelism all lead up to the great mystery of the Trinity. Indeed, it was impossible to explore these mysteries of scale, depth, and agency without falling into the triple cadence of trinitarian theology: the Spirit bearing witness to the Son; the Son revealing the Father; the Father having sent the Son and the Spirit for this very purpose. Salvation is an encounter with the Trinity, bringing about knowledge of the Trinity, through the effective work of the Trinity. The gospel is the good news of salvation worked out by the Father, Son, and Holy Spirit.

But even when these trinitarian depths of the gospel are recognized, it is still worth asking whether the doctrine of the Trinity needs to be made explicitly a part of the message in evangelism. Do we need to speak about the triunity of God when introducing people to the Christian faith? As a matter of technique, arguments could be made for holding off on it, or for diving right in. Obviously it’s a complex-sounding doctrine, which could be distracting. People who are vaguely aware of the doctrine may also associate it with irrationality, on the assumption that it teaches a contradiction. This objection can be met readily enough, but the argument itself is likely to lead a conversation further afield from gospel issues. So then, there is a good case to be made for postponing mention of the Trinity in evangelism.

On the other hand, inquirers need to be told about this doctrine fairly early, or they may feel cheated later, as if they’d been invited into the faith on the grounds of forgiveness but then were rudely shocked to learn that they had to swallow a difficult doctrine of God. Furthermore, there may be advantages to sharing this unusual-sounding doctrine earlier. Mightn’t the sheer oddness of it be rather compelling for a modern audience? Doesn’t it have just the right amount of peculiarity to it, the kind of peculiarity that marks the unpredictable reality of scientific puzzles? And if you are sharing the Christian message with a more intellectual acquaintance, isn’t there something helpful about having a really tough doctrine to ponder?

But these concerns are all in danger of bottoming out at the level of mere technique. They are not substantially different from the kind of calculations any salesman would make in communicating their message about insurance, pest removal, or costly repairs. The mystery of the Trinity points in another direction entirely: it points to the gospel as God’s own self-giving for our salvation. The good news that the Father sent the Son and the Spirit means that God did not delegate salvation, or carry it out by remote control, but came to be among us personally, historically, concretely. If anything calls us away from evangelism as mere technique, in danger of manipulation, it is a clear view of the trinitarian nature of God. Because the message of salvation is that God the Father so loved the world that he sent his Son, and that nobody can call the Jesus Lord except by the Holy Spirit, who was given to us so that we might understand what God has freely given.

In light of the trinitarian depth of evangelism, it’s no surprise that the key New Testament passages about missions and evangelism are prominent passages about the three persons of the Trinity. Consider Matthew 28:18-20: Jesus commissions his disciples to “go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you.” The sending out of the disciples happens on the basis of the Son’s glorification by the Father and the Spirit. Similarly, in the language of John’s Gospel, the risen Christ gives the trinitarian command, “As the Father has sent me, I am sending you,” and then breathes on them and says, “Receive the Holy Spirit.” (John 20:21-22) Sending verses tend to be Trinity verses. That is because Christian mission is the result of the Trinity’s own mission.

In passages like this, the biblical authors are not setting out primarily to teach the doctrine of God. Instead, what they are manifestly teaching about is the nature of salvation, and doing so in the context of mission and evangelism. But along the way, they necessarily include teaching about the God of that salvation, precisely in the form of references to the Son and the Spirit as sent from the Father. The close connection between salvation passages and Trinity passages is no mere coincidence. It arises from the fact that the Trinity and salvation belong together. The lesson this suggests is that while we don’t always have to talk about the doctrine of the Trinity in our evangelism, we do have to pay attention to the presence of God the Trinity in evangelism. Our evangelism is an extension of how the Trinity does evangelism. 

In his 1665 book Heaven Opened, Richard Alleine made “A Brief and Plain Discovery of the Riches of God’s Covenant of Grace.” Alleine announced the covenant of grace as “good news indeed,” and asked what was the content of the covenant that God had granted. What is in God’s plan of salvation? “In sum,” he said, “there is all that heaven and earth can afford; all that can be needed or desired; and this, by a firm and irrevocable deed, made over, and made sure to all that will sincerely embrace it.” In God’s salvation  we have three main things: God himself, God’s own Son, and God’s own Spirit. This encounter with God in his gospel is the blessing of salvation, and the proclamation of that good news never happens without the Trinity. It always happens within the Trinity.

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[1] J.I Packer, Keep in Step with the Spirit, 42.

[2] Sibbes’ book has a long and difficult original title but is usually referred to as “Sibbes on Union and Communion.” See The Complete Works of Richard Sibbes, vol II (Edinburgh: James Nichol, 1862, 174.

[3] Ursinus, “Hortatory Oration to the Study of Divinity,” in The Summe of Christian Religion (London, 1645), 6.