In an effort to be able to answer both at the same time, this outline should help to answer the question, Is the Bible something we can use to live by? To this question, the only reasonable answer is a definite Yes.
1. Yes, Because Its Author Is Divine
The Scriptures declare themselves to be of God. In II Timothy 3:16 the Bible tells us "All scripture is given by inspiration of God..." This word "inspiration" does not refer to the type of inspiration a poet, or a writer gets today. No, this was a special thing. It referred to the fact that "God-breathed" out the Scriptures from Himself. That is actually the Greek meaning of the word. In other words, the idea is that God so directed that "men of God spake as they were moved by the Holy Ghost" (II Peter 1:21), with the result that the words of the written Bible were inerrant (incapable of any error).
In applying this truth a little further, it can be seen that God was able to produce an infallible Book because He is Himself infallible. He also knows all things (omniscient), and He knows what we will need to live for Him.
2. Yes, Because He Has Given Believers His Spirit
This here is a point that needs to be very seriously considered. It is the dividing line between who can follow the teachings of the Bible, and who cannot. Having religion is not enough, and having the Ten Commandments is not enough to please God. He requires that we be made new by His Spirit - new, in the sense that our old way of life, and thoughts, are forsaken, and He moves in after baptism - and forgives the past transgressions, and His presence transforms the believer. Apart from this transformation that He makes in us, there can be no salvation. Christ died to bring us forgiveness, and redemption, and a new life - a life through the Spirit of God, and of His Son is us. His Spirit enables the believer to do what he could not do before.
3. Yes, Because It Covers All The Bases
Should the believer today live by the Bible? Yes, and he can, because God knew everything that he would ever face - through all the ages of the earth. The Bible was given, first to point mankind to the Savior, Christ, and then so "that the man of God may be perfect (mature), throughly furnished unto all good works" - this comes right after the above verse on inspiration. It is a Book that perfects the believer, and makes him so that God might be able to bless the life.
4. Yes, Because It Brings Blessing From Him
What a joy the believer has who seeks to be guided by the Bible! They are specially blessed by God Himself. In Psalm 1, the Bible tells us that, if a believer will walk different from those around him, and according to the Bible, that God will bless him - and he will be happy (not necessarily trouble free). In fact, the promise goes, if that believer will stay in the Bible, and daily think on its teachings with the intent to live by them, then God will bless them. His blessing will be compared to making them "like a tree planted by the rivers of water, that bringeth forth its fruit in its season; its leaf also shall not wither; and whatsoever he doeth shall prosper" (Psalm 1:1-3).
5. Yes, Because It Prepares Us To Meet Him
My final point is this, that the Bible should be followed because He gave it to prepare us. In the Bible we read of His love, and of His Sacrifice that Christ paid for us to be able to live with Him one day. Apart from some necessary do's and don'ts, the Bible is basically a letter of love - to the believer. When a believer follows the Bible, then the Spirit can guide him better, and give that person a greater joy and peace. Trouble comes so often for the believer - because we are not following Him. Obedience strengthens our relationship with Him. When a person loves God with all their heart, it is never an issue because then we will understand that all He wants us to do is because of love, and it will enable us to draw closer to Him in love. Following Him prepares us to live apart from sin, and in a sinless environment – Heaven itself.
David declared the condition of the believer who follows the Word carefully: “Blessed are they that keep his testimonies, and that seek him with the whole heart” (Psalm 119:2).
