I believe in the inerrancy, infallibility, and plenary verbal inspiration of the Bible. On what grounds do I hold such a view? Because the Bible says so. Jesus said that “the Scripture cannot be broken” (John 10:35). The apostle Paul, who was commissioned by Jesus, said, “All Scripture is inspired by God” (2 Tim. 3:16). In addition to the beliefs of Jesus Himself and His apostles we could add that, “the words, ‘The Lord said’, ‘The Lord spake’, ‘The word of the Lord came’, and cognate expressions are actually used 3,808 times in the Old Testament alone!” The testimony of the Bible concerning its divine origin is overwhelming, and that is my evidence for inspiration.
However, many will immediately object that this argument is invalid due to circular reasoning. They say we cannot use a source itself to prove its own authenticity. Rather, they say Christians are to look outside the Bible for evidence. That is true in most other cases. That is why we have lawyers, juries, witnesses, and so forth in a court case. If a man says he didn’t commit a murder, but three bystanders saw him do it, then his testimony is invalid. Or if a child says he saw the boogie man in his closet, no parent will believe them if the closet is empty.
The Bible’s claims concerning itself, however, are an entirely different story. Here, circular reasoning is appropriate. Why? Because it is God who is telling us this fact! What other evidence do we need? Whose words could I trust more? You see, unbelievers and liberal “Christians” do not see God’s testimony on the matter as valid. They hold Him to their own standards and demand that He present archaeological, historical, scientific, and philosophical evidence to back up His claim. They sit in judgment over God’s Word, rather than allowing it to judge them.
Why this case of circular reasoning is permissible and reasonable
Let us think of day to day interactions with people. Typically, we would believe a man’s testimony concerning himself. If a stranger tells me he is Norwegian, my first instinct would not be to call him a liar. I wouldn’t say, “Well, by your nose I can tell you’re actually from Spain!” Or if a stranger tells me their favorite food is spinach, I would not tell them they actually like oatmeal better. Everybody knows themselves better than anybody else. So it is with the Scriptures. How can we tell God that He is wrong about something He said of Himself? Why can’t we let the Bible tell us of its origin and nature?
Jesus Himself appeals to His own testimony as authoritative, as well as that of the entire Trinity concerning Him.
So the Pharisees said to Him, “You are testifying about Yourself; Your testimony is not true.” Jesus answered and said to them, “Even if I testify about Myself, My testimony is true, for I know where I came from and where I am going; but you do not know where I come from or where I am going. You judge according to the flesh; I am not judging anyone. But even if I do judge, My judgment is true; for I am not alone in it, but I and the Father who sent Me. Even in your law it has been written that the testimony of two men is true. I am He who testifies about Myself, and the Father who sent me testifies about Me.”John 8:13-14 (see also 5:31-47)
This form of circular reasoning is also good because it keeps God as the ultimate authority. You see, whatever else one points to as evidence will become the ultimate authority. If one says that the Bible needs to line up with their philosophy and reasoning, then they become authoritative. However, our method is better because it keeps God at the top. If we point a lost soul to history and science as their grounds for trusting God, then the minute some new discovery or study comes out that disproves the previous evidence, then their “faith” will be shattered. Further, our friend may simply be following the best debater. Anybody can be wrong on something and yet make a great sounding case for it.
Further, if we are finally convinced from those “higher authorities” that the Bible is God’s Word, then the Bible must afterwards become our authority. If that is the case, then we were wrong the entire time concerning those other supposed authorities. Let me reiterate that, for it is important. Suppose you say, “I won’t believe the Bible until history can prove it!” Then, enough historical evidence is given to convince you that the Bible is God’s Word, and it becomes your standard now. If that is the case, then was not the Bible the highest authority the entire time? Were you not wrong for denying God’s claim, and for demanding evidence?
What evidence would work?
Further, is there really any outside evidence that could possibly prove either position? Even if we had video cameras two thousand years ago and filmed the apostles as they wrote the original manuscripts, we would still be unable to prove that God’s Spirit was moving them. We would similarly be unable to prove that the Holy Spirit was not granting them utterance. However, being that the apostles were not filmed, what other evidence should we look for? No matter how many tablets or scrolls we dig up in the Middle East, we could never sufficiently prove either side of the debate.
Is the standard conformity to human philosophy? If so, then whose should we pick? No two philosophies about life agree. Is it conformity to scientific discovery? Many will say the Bible fails this test. Some apologists will try to explain why the Bible supposedly propounds a flat earth or will point to supernatural pre-scientific explanations of wind patterns or water currents as proof of the Bible’s accuracy. However, in most cases I would question whether or not the Bible was making a scientific claim.
I would not place young earth creationism in this category, however, because the Bible explicitly claims this on historical grounds. The Genesis account of creation is prose, not poetry. Further, the genealogies and records of kings’ rules, etc., which give the longevity of individuals as well as lengths of reign, firmly establish that the earth is only about 6000 years old. But here we have a conflict with modern science, to which I would ask, “Who was there in the beginning?” God was present at creation; therefore, I will believe His testimony on the matter.
Should the standard be our own experience? Read Jeremiah 17:9. That verse indicates our perception is terribly warped. Is the standard the absence of contradictions? The Bible meets this standard. Nine out of ten alleged contradictions can be brushed off instantly with a little common sense. As for the more challenging parallels which seem to be contradictory, I would argue that it is prideful to call it a contradiction too soon, without studying out the matter exhaustively. Perhaps a better approach would be to study the passages which claim inspiration. If no contradictions be found in those passages, then believe in inspiration. Then, being convinced of inspiration and therefore the absence of errors, then humbly approach other conundrums saying, “I do not get how they fit together now, but in heaven I will.”
We cannot even come up with a set of criteria for a divinely inspired document if we do not have one with which we could compare it! Whatever standard we hold the Bible or other “holy” books to is one that we fallen humans set up ourselves. But on our own we could never discover for sure what achievements it truly takes for a text to be “breathed-out by God.”
The kind of person we are dealing with here
To get a grip on this mind of inspiration deniers, remember the words of Abraham in the parable of the rich man and Lazarus, “If they do not listen to Moses and the Prophets, they will not be persuaded even if someone rises from the dead” (Luke 16:31). Those who reject plenary verbal inspiration are not victims of a world lacking the necessary research, but perpetrators rejecting their Creator’s authority.
Ephesians 4:18 speaks of fallen men “being darkened in their understanding, excluded from the life of God because of the ignorance that is in them, because of the hardness of their heart” (emphasis mine). This verse places things in the opposite order we would normally think. Typically we are tempted to sympathize with we are hard-hearted, saying God has not made Himself clear enough or something to that effect. However, here Paul reverses our thinking and grounds our ignorance in our hardness of heart! We do not acknowledge the things of God because we don’t want to! The same thought is found in Hosea where God says, “My people are destroyed for lack of knowledge” (Hos. 4:6). We think, “Those poor fellas! God should make Himself more obvious and then they’d be saved.” However, the next sentence says that they “have rejected knowledge” (v. 6, see also v. 11; 9:7; Isa. 5:11-13; Rom. 1:18-32).
So it is with rejecting God’s testimony of the Bible. If one demands that God answer to our scrutiny of His Word, it is not because He was careless in leaving archaeological evidence or preserving copyists from error; it is because of hardness of heart., 
 Lloyd-Jones, Martyn Great Doctrines of the Bible: Three Volumes in One (Wheaton, IL: Crossway, 2003), p. 25.  If you would like an interesting study on the matter, see Young, Edward J. Thy Word is Truth: Some Thoughts on the Biblical Doctrine of Inspiration [Grand Rapids, MI: Eerdmans, 1957], pp. 113-139. There he compares the Bible to standards drawn from the Koran, such as style and verbatim quotations.  The verses I cite in this section refer mainly to rejecting God all together, or rejecting the gospel. The verses do not directly refer to plenary verbal inspiration. However, the application of these verses can reach into other areas also, such as the case here. Also, to deny the gospel and the existence of God is to deny inspiration. Further, one can only hold those truths if they believe in plenary verbal inspiration (at least without being inconsistent).  For similar thoughts on circular reasoning, Goldsworthy, Graeme Gospel-Centered Hermeneutics: Foundations and Principles of Evangelical Biblical Interpretation (Downers Grove, IL: InverVarsity Press, 2006), pp. 32-33. Grudem, Wayne Bible Doctrine: Essential Teachings of the Christian Faith (Grand Rapids, MI: Zondervan, 1999), pp. 36-38. Stibbs, Alan M "The Witness of Scripture to Its Inspiration" in Revelation and the Bible: Contemporary Evangelical Thought ed. Carl F. H. Henry (Grand Rapids 6, MI: Baker Book House, 1969), pp. 107-118.