A great truth is that scripture is very simple to understand if one approaches it through faith. Of course there is a great difficulty of approaching scripture through faith.
The difficulty is not in the complexity of scripture, but rather often that we do not like the message the bible has for us. Our pride and often the lack of getting our way gets in the way of our understanding scripture. It is often not that we do not understand a text, but that we pretend not to understand because the message displeases us.
The bibles teachings on many issues are very simple for example the reality of hell. Of course there can be some difference on how literal to take the descriptions of the place, but the importance is the bible teaches it.
The reality is that man often approaches the bible in his sinful state and attempts to exert his will over scripture. Actually it is possibly the first sin of mankind, simply to say "did God really say."
Yes God did! He has said these things very clearly! The question of course is will we sit and listen to God and let God tell us the way things are? Or will we stand over scripture and tell God the way reality is.
The number of examples are limitless. There are many clear teachings of scripture ignored and often times the exact opposite of which are taught by "preachers."
Actually to preach is simply to open up God's word to others. To proclaim a message not from God is to not preach.
The bible does contain many things which are very hard to understand. To not understand all of scripture is normal. The reality is that God has made the very important things of scripture very clear.
There are teachings of scripture that are more or less important than others. All scripture is important, but not all scripture is as important as other parts. It has been my experience that the importantly vital parts of scripture are always explained in great detail.
And the important parts of scripture are repeated many times. Have you not understood Paul's explanation of faith then listen to Jesus' explanation of faith. There are four gospel accounts which feature many similar and some slightly different aspect of Jesus' teaching.
The teaching of scripture is a unity (scripture is not divided against itself) but scripture has offered many explanations of the important things of faith so that we can have many chances to understand. God does this because he loves us.
God is not a God who wishes to condemn sinners. In fact God is actively pursuing fallen men in the world. And he has a lot to say to them if they will come and listen.