I John 5:10 “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.”
The requisite to believe “on the Son of God” is to have “the witness” of God planted within our hearts and minds. Furthermore, “the witness” of God within us is the sure evidence to us that Jesus Christ is “the Son of God”; thus, He is God, He is our Savior, He is our Lord, He is our Master, and He is our sure hope of Eternal life. Those who do not believe “the witness of God” make “God” “a liar”; for, in addition to His “witness”/“record”, on two different occasions, God spoke and declared, “This is my beloved Son” (Matthew 3:17; Matthew 17:5). Thus, to “not” believe “on the Son of God” is to affectively declare that God has lied. This passage seems to address the Jews who had access to the Word of God; thus, they should have recognized “the witness of God” but they were so exalted within themselves and filled with their own sense of self-glory and power over the people that they ignored the obvious truth before them. This is an astonishing thing to me; for, to me, there is no greater source of peace and joy in this present world, than the blessed truth that Jesus Christ is indeed “the Son of God” and that He is my Savior (Matthew 1:21) and He is my “Good Shepherd” (John 10:11) in this present life!