Can you rely on the word of the bible? The best answer you can get naturally comes from the bible itself. Let me give you some bible words on the matter. Since today is Good Friday, I'll start with Jesus own prayer in the night before his death, where He says these words:

Joh 17:17
    Sanctify them through thy truth: thy word is truth.

When Jesus som hours later meets with Pontius Pilate, The question of truth comes up again. 

Joh 18:37-38
    Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice. [38] Pilate saith unto him, What is truth? And when he had said this, he went out again unto the Jews, and saith unto them, I find in him no fault at all.

 

God's word is truth. Jesus is the truth incarnated. The scripture cannot be separated from Jesus Himself, they come along. Paul writes these words in his second letter to Timothy:

2 Tim 3:16
    All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:

Paul declares that the whole bible is inspired by God. This is affirmed in several other passages. I will give you a couple of events when the inspiration from God comes before men: Two men are accompanied by the resurrected Jesus on their way to the little town of Bethany. As they were walking together, Jesus told them of the way that the scripture talks about Him:

Luk 24:44-45
    And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me. [45] Then opened he their understanding, that they might understand the scriptures,

Here is, as you can see, referred to the whole Old Testament. It is likewise in these words from Jesus when he is proclaiming Himself as the Son of God among a number of people who therefore want to kill Him:

Joh 10:34-35
    Jesus answered them, Is it not written in your law, I said, Ye are gods? [35] If he called them gods, unto whom the word of God came, and the scripture cannot be broken;

Peter writes about Paul's words in his epistles, in this way:

2 Pet 3:16
    As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.

You can see from this that Peter recognizes Paul's writings as unfallible scripture. That is what the scripture tells us all the way. It is the word from God. We have to rely on the scripture, even if we do not understand it fully: or rather even if we just understand it partially. It is like that, and it is just as it should be.
(to be continued)