1 John 5:9-13 NKJV
If we receive the witness of men, the witness of God is greater; for this is the witness of God which He has testified of His Son.
 He who believes in the Son of God has the witness in himself; he who does not believe God has made Him a liar, because he has not believed the testimony that God has given of His Son.
 And this is the testimony: that God has given us eternal life, and this life is in His Son.  He who has the Son has life; he who does not have the Son of God does not have life.  These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life, and that you may continue to believe in the name of the Son of God.