tl;dr A Biblical explanation for reliability of Scripture is that God does not allow God’s Word to fail.
We say information is “true” if it holds up under application and the examination of evidence and presuppositions for it. Hence the Christian assertion πιστὸς ὁ λόγος, reliable (trustworthy, infallible) is the Word[1]. The most natural understanding of this assertion is to say that the propounded Word, in whatever form, is like God, innately perfect and without error. However, this goes awry starting with the prophet, who, wrote Paul, perceives as through a murky glass, not to mention the limits of any person and language to describe what is perceived. For Scripture, the claim is even less robust; the discovery of a single jot or tittle out of place along the long line of translation, redaction, and reproduction disproves it — even the question of authoring is fraught. The Bible itself teaches that humans are prone to error, never mind that we have little idea of the whos or hows of most of Scripture. Whatever “God-breathed”[2] means, it cannot mean “inerrant,” for substantiated errors of more than one sort are present, if remarkably few.
There is, however, a second way the Word may be reliable. This is indicated, among other places, by the odd construction used to describe the career of the prophet in 1 Sam. 3:19: “Now Samuel grew, and the Lord was with him, and He let none of his words fail.” Whatever Samuel said, God made it true. Samuel was not innately inerrant or reliable. In a remarkable parallel to what Christians say Christ has done for any that believe, Samuel was made reliable by God’s action after the Word was preached. Indeed, the only way anything in a universally fallen world can be made reliable is by action and declaration of the One that defines and enforces inerrancy.
Amazingly enough, we have record of God doing the same for Scripture. It is fairly common knowledge now that the Greek Bible used in the Israel of Jesus’s day contained errors of translation. It’s been largely replaced in American usage by the Hebrew branch of copies, which is considered to be closer to whatever long-unavailable originals of both. This is why many New Testament references don’t match, like the ones about virgin birth (Masoretic reads “young woman”) or opening the eyes of the blind (Masoretic reads “remove the blindfolds”). The thing is, of course, that Christ is recorded as fulfilling the Greek Scripture that the people of his time and place had.
Our veneration of what is written is perhaps a wee bit excessive.
And here we may first suspect that our veneration of what is written is perhaps a wee bit excessive. After all, it takes a special kind of stubborn to consider how the blind and crippled were healed, evil spirits sent packing, and thousands fed out of thin air, and to respond with, “Well, there is a clan in Babylon[3] that say Isaiah didn’t write exactly this, you know.” What does that matter? Isn’t it still remarkable that the version of Scripture that was in use was fulfilled by these things? Or would lack of prediction in a better version mean these things were made up and didn’t really happen? If one thinks that, why bother appealing to Scripture at all?
Christ himself lampoons this mentality when, in response to how to apply Moses’s instructions[4], he bends down to start writing on the ground. It was a visual joke: we who came from dust and return to dust[5] write in the dust. And indeed, outside God to make it holy and eternal, is Scripture anything more than dust blowing in the wind? Scripture does mention (other) words written directly by God; they did not even survive the trip down Mt. Sinai, although they had been carved into stone[6]. Which means Jesus was making a Messianic claim of oneness with God with his “little joke:” Christ is the Word that Moses wrote from. And all of this, irony of ironies, in a passage[7] that does not appear in most of the earliest copies of this gospel.
To the contrary, Jesus consistently taught universal (among disciples) access to the Word[8] through the Holy Spirit. If we were to believe him, all copies of Scripture could be destroyed and erased from people’s memory, and we would still not lose access to God’s Word. And, indeed, Scripture itself records that it was, for all practical purposes, lost at least twice[9].
“Spirit” is ruach (breath, wind) in Hebrew, so “God-breathed” probably just means the usual way God creates[10] with the Word in the Holy Spirit. This, just of itself, implies nothing about the quality of human reception or reproduction. Where the Bible addresses the quality issue, it says it is faulty, which is why it mandates spiritual and communal procedures for assessing the reliability of what is received[11]. In that light, the doctrine of inerrancy applied to anything processed by humans can only be itself erroneous: an unnecessary and unbiblical rhetorical control[12] which only primes its believers for justified ridicule and manipulation[13].
[1] 1 Tim. 1:15 and elsewhere in the pastoral epistles. Ignore the translation choice of “saying” and compare to the exact same Greek wording applied to God elsewhere.
[2] 2 Tim. 3:16
[3] Masoretes, who faithfully made Hebrew copies of what we currently assume the Greek translation came from.
[4] The scribes and Pharisees are recorded as often prefacing their references to the Torah with the words, “It is written.”
[5] Gen. 3:19
[6] Ex. 32:19
[7] John 8:3-11
[8] John 14:26, Matt. 23:8, supported by the Epistles and OT
[9] 2 Kings 22, Neh. 8. Many believe Scripture was reconstituted under Ezra’s leadership.
[10] Genesis 1:9: God said… and it was so.
[11] See my book, Biblical Principles for Covenantal Prophets. It is too much to reproduce here.
[12] …much like the doctrine of cessation of prophecy
[13] A habit of denying plain evidence makes a person easy prey for lies and false doctrine.