1. CLarify

To understand where your friend is coming from, here are some questions you may ask:

·       What comes to mind when you hear the word “Trinity”?

·       Do you think that something can be real or true even if the exact word for it isn’t written down?

·       Have you seen any Bible verses that seem to point to the Father, Son and Spirit together? If not, why do you think Christians describe God this way? 

·       Which part of the idea of the Trinity feels confusing or hard to accept for you?

 

2.    Explore (Context) 

It is true that the term “Trinity” does not appear in Scripture. As such, your friend may find it unsuitable to describe God.

Your friend may also wonder if our belief in the Trinity shows that we have been influenced by pagan or polytheistic religions, where triads of deities are common (e.g., Zeus, Poseidon, and Hades of Greek mythology; the Trimurti in Hinduism).

It can also seem inconsistent when Christians firmly believe in God being one, yet speak of Him as three persons, which sounds like worshipping three separate gods.

To your friends from monotheistic religious backgrounds, our faith in the Trinity may be troubling. For others from polytheistic backgrounds, it may seem confusing.

  

3.    Agree 

It’s encouraging that your friend is trying to understand Christianity from the point of view of the Bible.

The Bible makes it clear that God is one. Deuteronomy 6:4 declares, “Hear, O Israel: The LORD our God, the LORD is one,” The Hebrew word used for “one”, echad (אחד), is the cornerstone of Israel’s foundational monotheistic confession.

God Himself repeats this truth in Isaiah 45:5, saying, “I am the LORD, and there is no other.” God also says, “Before me no god was formed, nor shall there be any after me” (Isaiah 43:10).

Christians fully affirm that there is only one God, eternal and unique. That is not up for debate.

 

4.    Reveal

The Bible teaches that God is one, but His oneness is a unity that allows for distinction. There are three distinct persons within this unity: the Father, the Son, and the Holy Spirit.

 

Just as Genesis 2:24 describes two distinct persons, husband and wife, becoming “one (echad) flesh”, echad can denote a unity that contains distinction. While the word itself does not prove the Trinity, it shows that God’s “oneness” does not necessarily mean a singular person.

The Old Testament provides glimpses of such distinctions within God’s unity. In Psalm 110:1, David distinguishes God from God’s chosen one, the Messiah (Jesus), yet calls them “the LORD (Hebrew YHWH or Yahweh)” and “Lord (Hebrew Adonai)” respectively. Isaiah 63:14 links the Spirit directly to God’s personal name Yahweh. Isaiah 48:12-16 likewise shows the Messiah identifying Himself as “the First and the Last” and declaring, “the Lord GOD has sent me, and his Spirit.” These passages demonstrate the three distinguishable figures in relation to the one God, laying the foundation for the Trinity referenced in the New Testament.

In the Great Commission, Jesus commands His disciples to “make disciples of all nations, baptising them in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19). Jesus speaks of one “name” while distinctly naming the Father, Son, and Holy Spirit.

In 2 Corinthians 13:14, the benediction, “The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all,” establishes the shared diving nature of all three persons.

Yet, such distinction does not mean division. The three persons act in perfect unity. The Father sends the Son out of love (John 3:16), the Son willingly lays down His life for humanity (John 10:17-18), and the Holy Spirit gives new life to those who believe (John 3:5-6). Each person is distinct in role, yet inseparable in purpose, working together to bring humanity into fellowship with God.

The Trinity is therefore not a human invention but God’s own revelation of himself as one God in three persons, eternally united in love and will. This matters because it explains how His love, power and presence reach us, and it shapes the Christian faith and mission.

The Trinity is also not simply an abstract explanation of God’s nature, but the foundation of Christian identity. Christians are saved by the work of the Triune God, brought into relationship with Him, and baptised into His name.