What they're really saying is what this Christian said;
"It is altogether possible to be instructed in the rudiments of the [Christian] faith and still have no real understanding of the whole thing. And it is possible to go on to become expert in Bible doctrine and not have spiritual illumination, with the result that a veil remains over the mind, preventing it from apprehending the truth in its spiritual essence...
"From lack of the vital Spirit [some] are forced to get along with the outward shell of faith, while all the time their deep hearts are starving for spiritual reality and they do not know what is wrong with them. This difference between the religion of creed and the religion of the Spirit is the difference between the letter of the Bible and the understanding that inflames the heart...
"The Scriptures, to be understood, must be read with the same Spirit that originally inspired them."
He concludes, "Jesus Christ is Himself the Truth, and He cannot be confined to mere words even though, as we ardently believe, He has Himself the Truth, and He cannot be confined to mere words, even though we ardently believe He has Himself inspired the words. That which is spiritual cannot be shut in by ink or fenced in by type and paper. The best a book can do is give us the letter of truth. If we ever receive more than this, it must be by the Holy Spirit who gives it."