Comma Johanneum

1 John 5:7-8
For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. And there are three that bear witness in earth, the spirit, and the water, and the blood: and these three agree in one. (KJV)
For there are three that testify: the Spirit and the water and the blood; and these three agree. (ESV)
For there are three that testify: the Spirit and the water and the blood; and the three are in agreement. (NASB)
For there are three that testify: the Spirit, the water, and the blood - and these three are in agreement. (HCSB)

The Comma Johanneum, also known as the Comma Johannine, is a textual variant in 1 John 5:7-8. The word comma simply means "short clause," and Johanneum means "pertaining to John."

This is the short clause: "three that bear record in heaven, the Father, the Word, and the Holy Ghost".

This only occurrence where God the Father, God the Son and God the Holy Spirit is counted like discrete objects and assigned numerical properties of the natural number 3.

The Bible has always been very careful to present God as one, and that He is God the Father, God the Son and God the Holy Spirit. While God the Father, God the Son and God the Holy Spirit is often seen simultaneously, interacting with one another, God is one.

In the Bible, God the Father, God the Son and God the Holy Spirit is always named distinctively, but never grouped or numbered, for example, like, "2 of the 3 persons of the Godhead" or "All the 3 persons of the Godhead".

Because of that, we can be sure that the Comma Johanneum is not part of the Bible, but inserted by theologians, who wanted to present God as 3-in-1, like some kind of coffee mix.

In your Law it is written that the testimony of two people is true. I am the one who bears witness about myself, and the Father who sent me bears witness about me." (John 8:17-18 ESV)