They are no different from the Jews in this passage. Man can say he believes the Bible exists. Yet that is observation not faith. Man can say the Bible is accurate in what it presents. Yet that is good scholarship, not faith.
Man can say the Bible contains good principles for living.
Yet that is only common sense and not faith. Man can say the Bible is from God and it is true in its entirety, revealing God's Word for man. And yet that is not believing the Word of God. To believe the Word of God is to not only attest to it as true but it is to trust in it as truth. Believing the Word is trusting in it for the very substance of our lives.