He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made Him a liar; because he believeth not the record that God gave of His Son. And this is the record, that God hath given to us eternal life, and this life is in His Son. He that hath the Son hath life; and he that hath not the Son of God hath not life.
These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.”  1 John 5:10-13  (KJB)

REFERENCES: 1 John 1 – 5; 2 John 1; 3 John 1; John 1:1-5, 14; 3:16; Colossians 1:16-17; Hebrews 12:1-2; Galatians 2:20; Mark 16:16; 2 Peter 1:10-11