7/3/12 V. 6, John points to three things that prove that Jesus is who he claimed to be and did what he claimed to do. The first two facts are that he “came” through water and blood. Because he came through these two things it follows best that John was speaking of Jesus’ baptism and crucifixion. These were two major points in Jesus’ life, the beginning of his public ministry and the end of it. Some also cite the blood and water from Jesus’ side at the crucifixion, which may play into it. But his baptism and his crucifixion would be primary.
The third testimony is the Spirit of truth, the Holy Spirit, who actually descended upon Jesus and proclaimed Jesus’ divinity.
V. 7, Later manuscripts include some extra information in this verse. Three testify in heaven, the Father, the Word, and the Holy Spirit, three in one. Most Bible translations do not include this since it’s seen as a later addition.
V. 8, These three, the water, blood, and Spirit all agree that Jesus was who he claimed to be during his time of ministry on earth. They fulfilled the prophecies concerning the Messiah.
V. 9, It’s true that the disciples and the people who knew Jesus also testified to his work and his divinity, which was good and valid; but the fact that God himself testified to it lays any questions to rest just because he’s God. We don’t need to question whether or not Jesus was the Messiah. We have all kinds of evidence showing that he was.