read in context the flow of chapter five in 1 John gives testimony of the Three that are One-i.e. the Godhead.
“For there are three that bear record in heavan, the Father, the Word, and the Holy Ghost: and these three are one.” KJV
1 John 5:7
Nearly all bible scholars acknowledge that this wording of 1 John 5:7 in the King James version is an addition to the original text. Ironically most think it was added because there was no clear statement about the holy spirit in heaven.
For example, the NASB reads:
1Jn 5:7 For there are three that testify:
1Jn 5:8 the Spirit and the water and the blood; and the three are in agreement.
For more information:
The Johannine Comma (1 John 5:7-8)