This is He who came by water and blood—Jesus Christ; not only by water, but by water and blood. And it is the Spirit who bears witness, because the Spirit is truth (1 John 5:6).
John becomes poetic, in my opinion. He is so thrilled with the Deity of Jesus that he sometimes leaves us behind in his vague euphemism of Christ, probably not wanting to overwhelm us. In this and the next two verses, John refers to three items: water, blood, Spirit. What is the water? It could mean his natural birth, his mother’s water. The Word of God is sometimes symbolized as water because it refers to the way the Word washes us. And finally, the water could take us back to the soldier who thrust a lance into the side of Jesus, already dead on the cross, yet water and blood shot out from his side. If you have watched Mel Gibson’s “The Passion of Christ,” he has the water and blood spraying over everyone around.
Blood can be His pure and precious Blood that paid for our sins on the altar in heaven, or simply the blood He dripped on the ground from the torture He endured. But the question is, what does all this mean? I like to look at this Scripture as indicating the Holy Spirit as the witness to all truth, and He will reveal the significance of the water and of the blood, as we are ready to receive all the revelation that John obviously knows. We, however, are still learning at the knee of the Holy Spirit.