Trying to understand the scriptures without understanding God is like trying to understand physics without understanding math. In many ways, math is the language of physics and many of its concepts can only be understood in the context of math. In the same way, the scriptures first treat of God before they treat of art, science, religion, or government. To fail to at least acknowledge God before one attempts to understand the scriptures puts their meaning and purpose beyond one's understanding and comprehension. By rejecting God we put the scriptures beyond our reach. When it comes to God, we reject in in three different ways.
First, we reject God by a rational dismissal of his existence from our mind and behavior. Paul, writing of the abundance of evidence that God has left behind in His creation relating to His own existence, said, "For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men who suppress the truth in unrighteousness, because that which is known about God is evident within them; for God made it evident to them. For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their speculations, and their foolish heart was darkened. Professing to be wise, they became fools... And just as they did not see fit to acknowledge God any longer, God gave them over to a depraved mind, to do those things which are not proper." (Romans 1:18-22, 28) This accurately expresses the state of our art, science, politics, and in some cases, even our religion today. Our president has come out stating that we are no longer a Christian nation, our scientists seek elaborate theories to explain away everything without having to invoke God, our media is increasingly parading the worst of behavior and licentiousness before our eyes while demeaning people of true faith, and in some religious circles, how a person feels has become more important than whom they believe and obey. With such a rejection of God there can be no understanding of the scriptures and their benefit in our lives are made null and void.
Secondly, we reject God by disobeying Him. Asaph wrote in a psalm, "But to the wicked God says, 'What right have you to tell of My statutes and to take My covenant in your mouth? For you hate discipline, and you cast My words behind you." (Psalms 50:16-17) To the contrast, Jesus spoke, "But go and learn what this means: 'I desire compassion, and not sacrifice.'" (Matthew 9:13) The scriptures cannot be understood purely from an intellectual perspective, they must also be learnt through experience; an experience gained through obedience. Knowing and even memorizing the scriptures does not guarantee the reaping of their benefits. We reap their benefits when we obey them and put them into practice in our lives.
Finally, we reject God when we doubt God. The writer of Hebrews, speaking of the ancient Israelites, wrote, "Therefore, let us fear if, while a promise remains of entering His rest, any one of you may seem to have come short of it. For indeed we have had good news preached to us, just as they also; but the word they heard did not profit them, because it was not united by faith in those who heard." (Hebrews 4:1-2) Faith is the handmaiden of obedience; you cannot have one without the other. In fact, where here he says they failed to enter because of their unbelief, later he says, "Therefore, since it remains for some to enter it, and those who formerly had good news preached to them failed to enter because of disobedience." (Hebrews 4:6) showing that faith and obedience are inseparably connected. There are many great promises in the scriptures and many benefits to be reaped through its knowledge and understanding, but none of these are available to us lest we mix our knowledge with faith. It is through faith that we inherit the promises (Hebrews 6:12) and it is through faith that we reap the benefits of the scriptures.