“Why We Believe What We Believe”
A series on theology & doctrine.
“Why We Believe What We Believe”
A series on theology & doctrine.

Why We Believe What We Believe: The Doctrine of the Trinity (Part 2)

When we think about this doctrine of the Trinity – that there’s three persons in one Godhead, Father, Son, and Holy Spirit – even for academics and Theologians, it’s a mind bending subject. It’s complicated.

Yet, Scripture has a lot to offer about the relationship not only within the Trinity, but as human beings relate to God.

Interestingly, apart from a Trinitarian Godhead, no one could be saved. In other words, if we don’t understand the Father, Son, and Holy Spirit, the role of those three persons; we don’t understand how a human being could be saved

This series was originally given to the students and faculty at Moody Bible Institute.

Show Notes


Apart from a trinitarian godhead, no one could be saved.

If we don’t understand the Father, Son, and Holy Spirit and their relationship to one another; we don’t understand how a human being could be saved.

Sometimes people talk about baptism and get upset about the mode, manner, etc. There are denominational splits over this.

Mark 1:9-11 There is an identification of the Father, with His Spirit, that Jesus is His Son.

The theology of baptism is identification: God the Father has identified His Son with the confirmation of His Spirit.

The believer is sealed (Gk. sphragizó, σφραγίζω) by the Spirit for the day of redemption. The trinitarian action in identifying the Son as part of the trinity, and identifying the believer as a believer in Jesus Christ.

Identification is the key issue.

The Great Shema: God is one

The Great Commission: The triune godhead sending us to make disciples.

The one reason I got baptized is because Jesus said “Baptize them”

The Great Authority: the Father, Son, and Holy Spirit are all God.

Ephesians 4:4-6
1 Corinthians 8:6

Here we have three persons equal in authority:

The Father is the source in this passage. All things exist for Him.

We exist through Jesus Christ, the agent of creation.

Galatians 4:4

The Great Unity

1 Corinthians 12:4-6

Gifts are given through the Spirit.

“The Divine Team” -JR Packer

The Father, Son, and Spirit are the same God but have diverse ministries.

We don’t have the word “trinity” in the Bible, which is important to acknowledge, but there are scores of scholarly texts that speak to this.

“In space you can move three ways: left or right, backwards or forwards, up or down. Every direction is one of these three or a compromise between them. We call them three dimensions.

If you’re using only one dimension, you could draw a straight line. If you’re using two dimensions, you could draw a square using four straight lines. And, if you add the third dimension, you could have what we call a solid body: a cube, or a box. It would be made of six squares in three dimensions.

Do you see the point? A world of one dimension would be a world of straight lines. A world of two dimensions, you would still see straight lines, but it takes many lines to make one figure. In a three-dimensional world, you still get the same lines but you get an advanced level of dimensions.

They are more real and more complicated in their levels. You still have them, they’re combined in many different ways, and you couldn’t imagine having them unless you knew the simpler dimensions.” – Ravi Zachariah, Can a Man Live without God?

If you want to measure a place in space, you have to have three points.

Why is a trinitarian doctrine important?

1. God had a perfect community in Father, Son, and Spirit and he wants that unity in the body of Christ.

2. God has incredible love for us. So, to express that love, it required His Son and His Spirit: apart from His Son there is no relationship and apart from His Spirit there is no connection. Jesus had to leave to send the Holy Spirit, which fulfills the new covenant.

We worship a God who has made a perfect way through His Son’s obedience and through sending His Spirit.

We don’t just believe the Bible because its the Bible. We don’t believe the Bible because it’s true. We believe it because God has revealed Himself through His word.

The only reason this book is true is because of the author.

The Bible is true because God is true.


  1. Salvation and redemption require a trinitarian godhead. We cannot be saved according to biblical theology apart from the Father, Son, and Holy Spirit. The Son pays for our sins, but the Spirit indwells us and fulfills the new covenant to show that we are saved and redeemed.
  2. Fellowship. If you’re going to have community, it takes someone who has a heart for community, and John 14-15 reveal a Father who has a heart for community with His own. Having a community of believers makes us better followers of Jesus Christ than we can be on our own.
  3. Access to God. Ephesians 2:18 The only way I understand the Bible or have intercessory ability with God the Father is because His Holy Spirit indwells me.

The moment we trusted Jesus Christ, the Holy Spirit became our permanent roommate to enable us to relate to Jesus Christ, who lives to make constant intercession before the Father, for us.

“You must simply believe this. No matter how clever, sharp, or intelligent a person might be, the human mind will never be able to fully comprehend it. If human wisdom were able to grasp this, then God wouldn’t need to reveal it in heaven or announce it in his holy scripture. So we should say, even though I cannot completely comprehend it, I believe it and I confess it: there is one eternal God who is also three distinct persons. The Holy Scripture is God’s Word and says that is the way it is. I will live by what it says.” – John Galvin

When we read the scripture, we make a decision: do we accept the Bible in its entirety as the word of God, or do we pick and choose parts of it?

If we are choosing to believe something and our eternal destiny hangs in the balance, we ought to be sure of what we believe.

The doctrine of the trinity is complicated; but it’s also rich, wonderful, and fascinating.

If we say we trust in Jesus Christ, then it follows to believe that His Word is sufficient to guide us as to how we ought to live our lives.

Have a Biblical or theological question? Ask Dr. E! Call us at 615-281-9694 and leave a voicemail with your question or email us at question@michaelincontext.com. Michael will answer it on an upcoming Ask Dr. E episode!

Michael Easley

About Michael Easley

Michael is husband to one, dad to four, and host of Michael Easley inContext.

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