The Bible asserts in several key scriptures that because the Bible is the word of God it carries the authority of God. Therefore, to disbelieve or disobey the scriptures is to disobey or disbelieve God. For instance, in John 17:17, Jesus declares in His prayer to God that “Your word is truth”. In doing so, He uses the Greek word “alethia” (225) which is translated “truth” and is a noun. In other words, the scriptures are not true (measured by another standard) but are themselves truth (the standard). This is further evidenced by the character of God as always telling the truth. For example, Balaam declares in Numbers 23:19 “God is not a man, that He should lie, Nor a son of man, that He should repent; Has He said, and will He not do it? Or has He spoken, and will He not make it good?” Also, because God’s word is truth, resulting from the fact that God speaks truth, His word carries authority because it is effectual—it accomplishes the purposes God intends for it to accomplish (Isaiah 55:11).
In contrast, people who reject the authority of scripture use various substitutes as their basis for final authority. For example, some people, particularly Catholics, substitute the traditions of the church for the authority of scripture. However, because church tradition is not inspired it is not adequate as a source of final authority. Also, some people use human experience and observation as the measure of final authority. However, there are limits to what people are able to perceive and understand and therefore human experience and observation are unreliable as sources of truth. Further, some people use science and philosophy as their final authority. However, because humans are not able to know all facts their conclusions cannot be 100% accurate. Finally, some people declare that, based on personal autonomy, they can decide absolute truth for themselves. However, no person is truly autonomous to the extent that they can decide what is true for themselves in a vacuum.