This article is from
Creation 40(3):44–46, July 2018

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Knock, knock … are you ready?

Get equipped for evangelism opportunities that come to your door!



It’s Saturday morning, and you’re enjoying your breakfast when you hear a knock at the door. When you answer it, you find some very nice people on your front porch, and they say they want to talk to you about God. While you might be put out at the early visit, this is actually a great evangelism opportunity … if you’re ready for it!

The most likely people you are going to meet in this way are Jehovah’s Witnesses and Mormons. In different ways, they deny central truths about God, such as the Trinity, the deity of Christ, and the personhood of the Holy Spirit. Because going door to door and talking to people is a big part of their religion, they spend a lot of time studying pre-rehearsed lines to defend the errors they teach regarding God.

Many Christians are intimidated when challenged by these groups, but if you are prepared with a few simple biblical truths, you will be able to refute their heresies with confidence, and share the Gospel with them at the same time.

A simple explanation of the true doctrine of the Trinity

While a lifetime of study of the doctrine of the Trinity will not exhaust its riches, the basic truths are simple enough for a child to understand:

God is One. There is only one God. Deuteronomy 6:4 says, “Hear O Israel, the LORD our God, the LORD is one.” He also pre-exists the universe, which He created.

The one eternal God exists in the three Persons of Father, Son, and Spirit. And this relationship is one of perfect harmony. They are equal in deity, glory, and power. As Wayne Grudem states, “The word trinity is never found in the Bible, though the idea represented by the word is taught in many places. The word trinity means “tri-unity” or “three-in-oneness”.

The three Persons are distinct. The Father is not the Son or the Spirit, the Son is not the Father or the Spirit, and the Spirit is not the Father or the Son. While the Persons always act in complete agreement and harmony, bringing about the will of God in all ways, sometimes this involves one Person doing something that the other two do not: for instance, only the Son took on human flesh in the Person of Jesus.

It is important to be able to state the main elements of the doctrine of the Trinity, because many heresies can be identified as twisting one of these elements.

Refuting errors about the Trinity

While there are lots of different groups that embrace errors about the Trinity, it is easy to sort them into groups and address the error that various groups have in common.

Unitarianism is the error of saying that God is one, and only one. Groups that believe this include Jehovah’s Witnesses, Christadelphians, and followers of Islam and modern Judaism.

Tritheism is the error that the Father, Son, and Holy Spirit are three gods, not one. There are not many people today who believe this, but it was a big deal in early church history. Some Muslims conflate the Trinitarian doctrine with tritheism.

Polytheism is the belief that there are many gods. Mormonism believes that Yahweh is one of many gods, and that humans may ascend to godhood themselves (see Genesis 3:5).

Denying the deity of the Son

One of the most common errors people make when talking about Jesus is to say that He was just a man, or that He was an exalted created being, but not God. Practically all cults make this error in one way or another. However, the Bible is clear that God the Son is eternal, and thus had no beginning. He is not a created being; rather, He is the agent of Creation, and He became incarnate in the Person of Jesus.

The beginning of John’s Gospel testifies clearly about the deity of Christ: “In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God; all things were made through him, and without him was not anything made that was made” (John 1:1–3). There are many other passages that testify to the deity of the Son, including Titus 2:13, which calls Jesus “our great God and Saviour”, and Colossians 2:9 which states that “the fullness of deity” dwells bodily in Christ.

Many cultists have ready-made responses to the most common passages that are cited regarding Jesus’ divinity, such as John 1. So it is useful to have some less-commonly cited passages ready at hand. For instance, in John 12:37–41, John cites Isaiah 6, and says, “Isaiah said these things because he saw his [Jesus’] glory and spoke of him”. Yet when you turn back to Isaiah 6, Isaiah saw Yahweh’s glory. This means John is identifying Jesus as Yahweh.

Denying the Personhood of the Spirit

Many cults say that the Holy Spirit is not a distinct Person, but a way of speaking about the power of God, or a ‘force’. Jehovah’s Witnesses make this error, but many Christians also erroneously downplay the Personhood of the Holy Spirit.

In Scripture, the Spirit interacts with the Father and the Son. He also indwells, comforts, and empowers believers. He can be grieved. He even speaks saying “me” and “I” (Acts 13:2). These are not the actions of an impersonal force, but of a Person. He (not it!) has the same glory, and is as worthy of worship, as the Father and the Son.

Confusing and conflating the Persons of the Trinity

Unfortunately, many Christians confuse or conflate the Persons of the Trinity. Because much teaching in this area is deficient, many Christians formally believe in the Trinity, but their descriptions of the Trinity are actually unbiblical.

One of the most common errors is called ‘Modalism’. This is the belief that the Father, Son, and Holy Spirit are all manifestations of the same Person. In the Old Testament, we see the Father. Then in the Gospels we see Jesus, and after Pentecost we see the Holy Spirit. But in the Bible the three Persons interact with each other, meaning that they cannot be the same Person ‘wearing different hats’.

Some errors conflate the actions of the Persons. For instance, Patripassianism asserts that the Father suffered on the Cross. The popular (and unbiblical) movie The Shack portrayed ‘Papa’ with scars on ‘her’ wrists, compounding error upon error.

The Trinity and salvation

Each of the three Persons in the Trinity is active in the salvation of those who trust in Him. The Father put the plan of salvation into place before the world was created. The Son became incarnate, lived a righteous life, and died as a sacrifice for sin so that all who would believe in Him could be pardoned and credited with His righteousness. He then rose from the dead. The Holy Spirit indwells, sanctifies, and empowers believers. While this hardly exhausts the ways in which the Trinity acts to save believers, this shows how important it is to have a correct understanding of this important doctrine. A wrong view of the Trinity inevitably warps our view of salvation.

Answer the door with confidence!

As Christians, we should be prepared to explain the basic doctrines of our faith with unbelievers and cultists at any time—even if too early on Saturday morning! Some dedicated study can help you to be ready to take full advantage of opportunities to share the Gospel.


The Trinity and Creation

The very first action attributed to God is creation. God alone is uncreated and not dependent on anything. While there is a hint of God’s plurality in His use of the plural in Genesis 1:26 and elsewhere, the Old Testament does not explicitly teach the Trinity or detail how the different Persons acted with regard to the creation.

The New Testament reveals that the Son was the agent of creation. John says of Jesus, “Through him all things were made, and without him was not any thing made that was made” (1:3). He also has a role in upholding the creation. “For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him. And he is before all things, and in him all things hold together” (Colossians 1:16–17).

While we do not get a clear picture of what the Spirit did in creation, we are told that He was hovering over the face of the waters (Genesis 1:2). He may have been the Person to imbue life into human beings (Job 33:4; Psalm 104:30).

Scripture passages that show the Trinity

Matthew 3:16–17

And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him; and behold, a voice from heaven said, “This is my beloved Son, with whom I am well pleased.” (The three Persons all appear in this scene—Jesus is being baptized, the Spirit is descending like a dove, and the Father speaks from Heaven).

Matthew 28:19

Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit. (The Father, Son, and Holy Spirit have the same name, not names, and they are mentioned without any hint of hierarchy).

Romans 8:16

The Spirit himself testifies with our spirit that we are the children of God, and if children, then heirs—heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him. (The Spirit testifies we are children and heirs of the Father and co-heirs with Christ, the Son).

1 Corinthians 12:4–6

Now there are varieties of gifts, but the same Spirit; and there are varieties of service, but the same Lord; and there are varieties of activities, but it is the same God who empowers them all in everyone. (This is one of many Trinitarian formulas in Paul’s letters—the Spirit, Son, and Father are referenced deliberately—this does not directly teach the doctrine of the Trinity, but it assumes it.)

Posted on homepage: 7 October 2019