Whoever believes in the Son of God has the testimony in himself. Whoever does not believe God has made him a liar, because he has not believed in the testimony that God has borne concerning his Son. And this is the testimony, that God gave us eternal life, and this life is in his Son. 1 John 5:10-11
Please read and or listen to 1 John 5:6-12. In this section, John talks about the testimony that allows his readers to know that Jesus is who he says he is. Water, blood, Spirit. While there are several views on what is meant by the water and blood, it seems best to consider it to be the water of the baptism that launched Jesus’ earthly ministry and the blood of his sacrifice on the cross. Cerinthus, who was a contemporary of John and a false teacher, taught that the divine Christ came upon a human Jesus at his baptism and then left him before his death. This false teaching was beginning to influence those in the church and so, as John gives the testimony of the water and the blood, he is stating that that teaching is categorically false. In addition, to complete the need for three witnesses, he reminds them that the Spirit testifies as well. In addition, God testifies to the truth of Jesus being fully God and fully man (Matthew 3:17, 16:15-17). Finally, the testimony is in everyone who has been born of God. The testimony that is in us is that God is the giver of eternal life through his Son. We can now know God (John 17:3) and be sure of eternity with him. That knowledge within ourselves brings a testimony that validates that Jesus is the one true Son of God. Whoever has the Son has life, whoever does not have the Son does not have life. Do you have the Son? Is your life a testimony of the truth of who Jesus is?