May 16, 2024

What Jesus Taught about the Trinity

Sinclair Ferguson
What Jesus Taught about the Trinity

Some Christians wonder if the Trinity is an impractical doctrine. Yet Jesus devoted some of His most important hours with the disciples to teaching this truth. Today, Sinclair Ferguson focuses on Jesus’ words in the upper room.


We’ve been thinking this week on Things Unseen about the doctrine of the Trinity, and I’ve been trying to explain a little of why it’s so important. I’ve suggested a couple of times now that I think many Christians see it as a kind of speculative and impractical doctrine, and I’ve been trying to say it’s the very reverse. So today I want to try to show in another way why it is so practical, and maybe I can express it in kind of in-your-face way by saying: “Trinity, the least practical doctrine? Tell that to Jesus.”

What do I mean? Well, when another Christian seems to express a negative opinion about any Christian doctrine, it’s always actually a good pastoral move to say, “Did Jesus say anything about this?” After all, as Christians, we understand that we love and that we trust Jesus. If He believed something, then we are called to believe it. If He thought something was important, then surely we should too. So, where does that take us?

Well, one place it takes us to is the upper room and to the last few hours before Jesus was arrested, recorded in John 13–17. Read through them sometime, asking yourself these questions: Did Jesus think the Trinity is important? And did Jesus think knowing the Trinity would make any difference to the Christian life? I think what you’ll find in these chapters is a magnificent tapestry of gospel grace, woven from three threads: the work of the Father, the work of the Son, and the work of the Holy Spirit. These were, after all, the most sacred hours the disciples had thus far spent with Jesus, and this was certainly the most profound teaching He’d ever given to them. He’s teaching them what they needed to know in order to live at a time of great crisis. He was teaching them what was really important, and what He was talking about was the Trinity.

He tells us about His own relationship with the Father and His own relationship with the Spirit—how the Father loved Him and had committed to Him the work of redemption, how Jesus Himself had honored and glorified the Father, and He spoke too about the way in which the Holy Spirit was His Holy Spirit and that He would send that Holy Spirit to them.

So, what was happening in the upper room was that Jesus was talking essentially about the Trinity. He was talking about an event that would take place in His crucifixion, and in His resurrection, and in His sending of the Holy Spirit, in which all three persons of the Trinity would share—the Father, the Son, and the Holy Spirit.

In Jesus, the disciples had seen the Father. Remember how when Philip said, “Show us the Father, and that will be enough for us?” Jesus indicated to him, “But Philip, you’ve seen who the Father is by watching me, by my relationship to Him.” And in a sense, He’s answering the same question in John 13–16 about the Holy Spirit. “The Holy Spirit,” He says, “you know Him because He’s been with you and He will be in you.” The Spirit of the Father and the Spirit of the Son, one Spirit had dwelt on Jesus’ life for these thirty-three years. “And now,” says Jesus, “He’s going to come to indwell you. And when He comes to indwell you, what will happen is that your life will become a place, a home, where the Father and the Son will come to dwell.”

It is absolutely extraordinary, amazing, wonderful teaching. You see what this means? Remember yesterday when we were talking about baptism? Well, we’re called to live the Christian life as those who belong to the family of God. We’ve been named for the Father, the Son, and the Holy Spirit—for the Trinity. That’s our new family name. But it’s not just a formal thing. It’s an amazing, glorious reality in which, by the indwelling of the Spirit, not only does the Spirit indwell us, but through the Spirit, both the Father and the Son come, as Jesus says, to make our lives their home.

I don’t think there’s anything more practical than knowing that that’s true of you. Many years ago, J.B. Phillips, famous for his paraphrase of the New Testament, wrote a little book with the title, Your God Is Too Small. It’s not really about the Trinity, but I think those words do apply to our appreciation of the Trinity, because if we’ve thought about the Trinity as a speculative and impractical doctrine, then our God is too small. And that means it’s time for us to think again, and we’ll think again about the Trinity for the last time this week tomorrow.