In modern statements of faith, the connection between inspiration and inerrancy is made plain, such that Christians believe the concept of inerrancy is necessary to properly define inspiration. But that is incorrect. In fact, the idea that the scriptures are trustworthy and infallible is an ancient Christian teaching, whereas the idea that the Scriptures are inerrant is a modern conceit.
First, it depends what exactly is inerrant: the Sacred Scriptures that make us wise unto salvation (the forma), or the text—the peculiar combination of marks on a page (the materia), which change from language to language, and from translation to translation. These textual differences can be significant. A particular word may have a subtle range of meanings in Hebrew, but when that word is translated into Greek, the translator picks one word to represent the primary meaning. Thus the act of translation is an act of textual interpretation.
Second, if one postulates the verbal (and plenary) inerrancy of the autographs (being the original peculiar combination of marks on a page), this postulate then drives the task of textual criticism. No longer do textual critics seek determine the authoritative text (a theological enterprise), but instead seek the recovery of the original text (a critical enterprise), which they deem authoritative by virtue of its being original. The search for the original text is itself an act of textual interpretation. Although textual criticism proceeds on the basis of rules, and gives the appearance of being scientific, the rules are in fact arbitrary, based on assumptions made before one approaches the text. For example, if you favor the Masoretic text of the Old Testament, your rules will give primacy to that text and other texts will be of secondary importance.
Verbal inerrancy in the autographs necessitates the understanding that only the original author was inspired by the Holy Spirit, and that subsequent corrections, additions, and deletions by later copyists and/or churchmen are corruptions. The clear implication is that the word of a particular man (the author) was inspired; indeed, that the author was himself inspired. When Peter writes of the “holy men of God who spake as they were moved by the Holy Ghost” (2Pe 1:21), the assumption is this applies to the particular man or prophet who initially produced the writing, as opposed to the later copyists and churchmen who modified the text in one way or another. This means that passages deemed by both conservative and liberal scholars to have not been part of the original text are suspect, even though the extant texts are part of the canon of Sacred Scripture. The natural result is the re-opening of the canon of scripture and the excision of suspect texts from Sacred Scripture. The obsession with verbal inerrancy logically leads to the error of Marcion.
There is another way of thinking about all this. What if we ignore the minor errors of scripture? As a practical matter, we do that already. Do we really care that 1 Kings 4:26 says that Solomon had forty thousand stalls of horses, whereas 2 Chron 9:25 says Solomon had four thousand? No, of course not. We recognize that a copyist made an error and move on. It is not germane to the subject at hand, and represents no threat to the inspiration and trustworthiness of Scripture. The only way this becomes a problem is if we begin to incorporate modern understandings of inspiration into our thinking, which requires a series of rationales and tendentious arguments for each and every difficult passage in the Bible.
A literalistic understanding of Sacred Scripture can lead to all sorts of problems. For example, the United Methodist Minister Richard Hagenston writes of the direct contradiction contained in the final verses of Psalm 51. In his analysis of this passage, verses 16-17 indicates that God does not want sacrifice, while verses 18-19 says that God is pleased with sacrifices. So which is it?
For thou desirest not sacrifice; else would I give it: thou delightest not in burnt offering.
The sacrifices of God are a broken spirit: a broken and a contrite heart, O God, thou wilt not despise.
Do good in thy good pleasure unto Zion: build thou the walls of Jerusalem.
Then shalt thou be pleased with the sacrifices of righteousness, with burnt offering and whole burnt offering: then shall they offer bullocks upon thine altar. (Ps 51:16-19)
You, dear reader, may find it interesting to compare different approaches to this passage. Richard Hagenston’s approach is to take the text at face value. The text means exactly what it says, and has no deeper meaning. The literal interpretation is the only interpretation, you might say. And having said that, we are left with a rather glaring contradiction.
Most other Bible scholars would look at this passage in its context of the Psalm as a whole. Since the overall theme is of repentance, verses 16-17 would indicate that God prefers repentance to sacrifice; verses 18–19 says that God is pleased with sacrifices when they are offered with a repentant heart. But note that this interpretation goes beyond the literal meaning of the text, and depends upon the idea that the text contains deeper meanings than the mere literal reading can reveal.
To a strict literalist, the passage in Psalm 51 represents a contradiction, which is clearly an error. The accumulated weight of these errors (and others, of different types) drives some, like the scholar Bart Ehrman, to a loss of faith in God. For others, like Richard Hagenston, these errors drive them to a loss of faith in the Bible, and a questioning of doctrinal orthodoxy. All because we conflate inspiration and innerancy. God help us.
Hagenston, R. (2014, September 29). 8 Things Your Pastor Will Never Tell You About the Bible. Retrieved October 4, 2014, from Patheos.com: http://www.patheos.com/blogs/friendlyatheist/2014/09/29/8-things-your-pastor-will-never-tell-you-about-the-bible/
 The search for the original text ignores the fact that the bible has a history, and that the collection of texts into the canon existing today was curated by the Church. The search for the original text must yield to the search for the authoritative text. In turn, this means that we can only understand the bible within the community that curated it, within the “matrix that includes the thoughts and writings of the early church: its bishops, priests, poets, monks, theologians, and artists.” (Miller 2012)
 Favoring the Masoretic text may seem reasonable, as (apart from the Dead Sea Scrolls) it is the most ancient extant Hebrew text. There is a marked preference for translating the Old Testament from the Hebrew text, a preference that goes back to the Renaissance Humanists who argued for a return to the sources. The rallying cry of this movement was the Latin phrase “ad fontes“, meaning “to the sources.” The reformers, being products of their time, thought that using Hebrew sources rather than the Greek translation was right and proper.
 Interesting examples include the following: 1) The epilogue of John 21 may have been added later. The original Gospel appears to end at Jn 20:31. 2) The pericope on the woman taken in adultery (Jn 7:53 – 8:11) is not in the oldest and best-attested manuscripts. 3) The oldest manuscripts for the Gospel of Mark do not include Mk 16:9-20; instead, it ends rather abruptly with the resurrection appearance to Mary Magdalene. This all results in the following question: if the Sacred Scriptures were inerrant in the original manuscripts, and these texts were not part of the original text, are they then Scripture? Do we excise them from our bibles? And if so, how is this different from what the heretic Marcion tried to do?
 (Hagenston 2014)