1 John 5:7–8
 For there are three that testify:  the Spirit and the water and the blood; and these three agree. (ESV)
Jesus is the Christ. He is the promised Messiah. He is the anointed one. There are many proofs of this, and in these verses the Apostle John gives three evidences that testify to Jesus being the Christ: the Spirit, the water, and the blood.
 how God anointed Jesus of Nazareth with the Holy Spirit and with power. He went about doing good and healing all who were oppressed by the devil, for God was with him. (ESV)
The Holy Spirit actively guides and directs all things. The entire Bible was written by men who were guided directly by the Holy Spirit. At the Creation of the World we find the Holy Spirit. At Jesus' baptism we find the presence of the Holy Spirit. The Holy Spirit raised Jesus from the dead. And we have access to that very same Spirit.
When Jesus was baptized he demonstrated for us what we all should do. Water is what we use to cleanse things. Waters of baptism demonstrate that we have been cleansed of our sins and raised from the death of sin to new life in Jesus Christ. Jesus himself was baptized, not because he had any sin, but as a public demonstration of his purity.
Where would we be without the blood of Jesus Christ. Scripture declares that there is no forgiveness without the shedding of blood. In the Old Testament the blood of bulls and goats was shed for forgiveness, but they were not sufficient. Only Jesus' blood shed for us provides the forgiveness we need. He was willing to shed his perfect blood for our sins. His blood is evidence that he is the Messiah.
Jesus is the Christ. There are many proofs. Included in those proofs are the Spirit, the Water, and the Blood.