Mt 3:16-17, Jn 1:33, Jn 19:30, Heb 9:14
God and the Holy Spirit testify that Jesus is the Christ. (1 John 5:6-8, Matthew 3:16-17, John 1:33)
1 John 5:6 This is he that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth. 7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. 8 And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.
Matthew 3:16 And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him: 17 And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
John 1:33 And I knew him not: but he that sent me to baptize with water, the same said unto me, Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Ghost.
Jesus did the work of Christ by shed His blood on the cross to forgive our sins. (John 19:30, Hebrews 9:14)
John 19:30 When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost.
Hebrews 9:14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?