Without revelation from God Himself about Himself, we would be extremely deficient in our understanding of the spiritual world and of eternal things. God has taken the initiative to show Himself to us, where we fit into the grand scheme of things, and especially the relationship that He has created for us with Him.
You may have questions about the absolute authority of Scripture. The basic question about that authority comes to this: "What do you think of Christ?" If we accept Him as Lord, it's consistent to submit to His teaching on the complete authority of Scripture.
In Matthew 5:17-19 Jesus declared that
"Heaven and earth would sooner pass away than the dotting of an 'i' or the crossing of a 't' from the law."
In Luke 16:17 He adds that it is impossible for one particle of the law to be set aside as void, and in Luke 24:25 He rebukes His disciples for not believing all that the prophets had spoken.
In John 10:34,35, in controversy with the Jews, He argues that Scripture cannot be broken, dissolved, or discarded. In Mark 7:6 and following we see that in the thought and teaching of our Lord, the law of Moses is explicitly labeled the word of God.
But you may ask, "Isn't this a circular argument? All we know about Christ we learn from the Bible. Unless we presuppose our conclusion, the entire case based on Christ has no foundation."
This emphasis on authority does not fall into this vicious circle. Faith in Christ as Lord and Savior doesn't necessarily depend on prior faith in an infallible Bible. The Christian doesn't insist that one must believe everything in the Bible before he is convinced of anything in it.
We initially come to Scripture as C. S. Lewis did. He based his faith in Christ on the general reliability of the New Testament documents as proved from history: the historical evidence for Christ's sinless life, the genuineness of His miracles, His stupendous claims as to his own person, and His bodily resurrection from the dead. He was drawn to Christ by the work of the Holy Spirit who created a true faith in him personally.
The Christian faith doesn't logically presuppose as its basis an infallible Bible, but only a New Testament that is true in its main points. The case for the authority of the Bible, therefore, is not circular but structurally valid.
We are driven back to the real issue which thinking men must not avoid: "What do you think of Christ? Is He the final authority over our life and thought, or is he not?"
If He is not, that settles the matter of divine authority of Scripture. If the Bible is wrong at this main point, it is certainly wasted effort to discuss its infallibility. Many have taken this position and thus willfully placed themselves under the judgement of the God they choose to disbelieve and ignore. They choose to place their limited knowledge at a higher value than the revelation of information that comes from beyond their source of knowledge.
If, on the other hand, Jesus Christ is really divine Lord and Savior, that too settles the matter, and we should hear no more about accepting Christ but not the Bible. He has sent His Spirit to help each of us understand the truth in the Bible, and to enable each of us to apply it and obey it.
Properly understood, the Bible is believable. Our Lord commanded us as His disciples to believe it. For those of us who seriously call upon Him as Lord, there is no alternative but to accept His word. We are under orders.
The evidence is overwhelming that Jesus Christ not only claimed to be Lord but insisted that His disciples submit to His lordship by obeying Scripture. Our difficulty is not whether the Bible is infallible or authoritative, but is in obedience to its teaching.
If we believe that the Bible is true, carries divine authority, and is the source of our knowledge about Christ and His will, then we should study it. And as we do, our Lord has promised His present indwelling Holy Spirit to guide us to Biblical truth.
Jesus Himself said that we, as His followers, will be hated by the world because He is hated by the world (John 15), and He said that there is a wide way that leads to destruction, and a narrow way that leads to life (Matthew 7). There are many falsehoods but only one truth. We know we are onto truth when we find ourselves very much alone in the world. And we will know the truth, and the truth will make us free (John 8). Once we see the truth we cannot "unsee" it. Like a hidden image in a painting -- once you see it you will always know it is there. The Holy Spirit gives great confidence and assurance about truth that is difficult to attain on human terms.
Paul describes how truth is spiritually discerned in 1 Corinthians 2:9-16:
"Just as it is written, 'Things that no eye has seen, or ear heard, or mind imagined, are the things God has prepared for those who love him.' God has revealed these to us by the Spirit. For the Spirit searches all things, even the deep things of God. For who among men knows the things of a man except the man's spirit within him? So too, no one knows the things of God except the Spirit of God. Now we have not received the spirit of the world, but the Spirit who is from God, so that we may know the things that are freely given to us by God. And we speak about these things, not with words taught us by human wisdom, but with those taught by the Spirit, explaining spiritual things to spiritual people. The unbeliever does not receive the things of the Spirit of God, for they are foolishness to him. And he cannot understand them, because they are spiritually discerned. The one who is spiritual discerns all things, yet he himself is understood by no one. For who has known the mind of the Lord, so as to advise him? But we have the mind of Christ.
A radio receives a signal only when it is tuned to the correct frequency. So too, we only receive spiritual understanding when our hearts and minds are tuned by the Spirit. The Spirit is given to us when we respond to God in Faith, and Romans 10:17 says:
Faith comes from what is heard, and what is heard comes through the preached word of Christ.
You can't partially test faith, you must commit to faith for it to change your life and understanding. That's when truth becomes clear rather than just foolishness and irrelevant. Faith is a commitment, not just an opinion.