We have looked before at 1 Corinthians 2:14 that explains why unbelievers cannot understand the Word of God:
But the natural, nonspiritual man does not accept or welcome or admit into his heart the gifts and teachings and revelations of the Spirit of God, for they are folly (meaningless nonsense) to him; and he is incapable of knowing them [of progressively recognizing, understanding, and becoming better acquainted with them] because they are spiritually discerned and estimated and appreciated
"My Utmost For His Highest" by Oswald Chambers for today shows us the reason that many born again believers do not have knowledge of the Word either.
The golden rule for understanding spiritually is not intellect, but obedience. If a man wants scientific knowledge, intellectual curiosity is his guide; but if he wants insight into what Jesus Christ teaches, he can only get it by obedience. If things are dark to me, then I may be sure there is something I will not do. Intellectual darkness comes through ignorance; spiritual darkness comes because of something I do not intend to obey.
I remember hearing Kenneth E. Hagin share how the Word of God became closed to him after he saw in the Word that he was not supposed to worry and decided that this was not possible for him to do. He would read the Word as before, but it became dry and meaningless to him. When Brother Hagin went back to that choice, he decided to agree with the Word of God and the Spirit of God and to STOP worrying! When he did that, the Word opened up to him again! So, if the Word has become dry and lifeless to you, or if you are simply not understanding it, go back to the last thing that you knew to do and decided NOT to do it. Make the adjustment and the decision to obey what the Word says and the Word will open up for you again! AMEN! Here is Hillsong with "To Be Like You":
Shalom in Him!