One of the great mysteries of our God is that He is a triune God. We serve one God, but He exists in three persons. He is not three different gods, but the one true God, existing in three persons who are all equal. The Father, Son, and Holy Spirit are of the same essence. There is not space enough here to do an in-depth explanation of the Trinity. My purpose here is to warn against a wrong understanding of the Trinity because it is of vital importance to understanding the gospel.
If you believe the Bible to be the inerrant, infallible Word of God as I do, then we must recognize there are mysteries in it we cannot understand in our humanness. Some day God will make it clear. For now, the Trinity must be something we accept by faith, even though we do not comprehend its possibility.
Popular (but wrong) teaching about the origins of the Trinity point to its creation as a school of thought around 300 AD. Some scholars attribute its creation to Tertullian, one of the early church fathers. However, we find references to the Trinity in the Bible, texts that significantly predate both Tertullian and the year 300 AD. Paul mentions the Trinity in closing his second letter to the Church in Corinth (2 Corinthians 13:13). He signs off by saying, “The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with all of you.” (NOTE: some versions of the Bible split verse 12 differently, resulting in this reference to the Trinity being in verse 14. The verse numbers were inserted by man and do not change the words of God, just how various scholars organized them for readability). Paul understood God exists in three persons as a triune God.
In the book of Revelation, we see John also understood God to be triune. In Revelation 1:4-6, we see God the Father as the one “who was and is to come”, the Holy Spirit as the seven-fold spirit before the throne, and Jesus the Son as the faithful witness and firstfruits of the resurrection. As far back as the first chapter in the Bible, we see the Trinity on full display. In Genesis 1:26, God says, “let us make man in our image. Notice the plural references there. Genesis 1:2 tells of the Holy Spirit hovering over the dark void that existed before God spoke the world as we know it into existence through His Word, Jesus. We know Jesus was the Creator of all things because John tells us He was with God in the beginning, and nothing was made except through Christ (John 1:1-3).
The Trinity is not some man-made concept. It is the reality of who God is, presented in the first book of the Bible, again in the last, and throughout the pages in between. The Trinity is a mystery, impossible to explain or grasp fully. It is nonetheless true and one thing that sets our God, the one and only true God, apart from all the other man-made gods throughout history. It speaks to the unfathomable depth, power, and glory of our Lord and King. That this unfathomable God also desires to both know and to be known by us is a great mystery. It is the privilege and honor of our lives. God chose us to live in fellowship with Him. There is no greater honor. The triune God is complete unto Himself, yet His love for us compels Him to seek us. What an awesome truth. What an awesome God.