I have heard you use the term “textual criticism” before. What is this?
Textual criticism, also known as “lower criticism,” as noted by F.F. Bruce, “is the restoration of the wording of a document when alterations have been introduced (deliberately or inadvertently) in the course of copying and recopying. Before the invention of printing, when each copy of a document had to be written out separately by hand, scribal errors were especially apt to occur” (ISBE). It is employed to determine what the original reading of a Biblical text was, taking into account the oldest available texts and textual fragments of Scriptures, ancient translations of Scriptures available, and quotations of Scripture in ancient literature. The same entry goes on to state,
“If the autograph or original document survives, scribal errors can be corrected by reference to it. But if it has long since disappeared (as has happened with all the original emplars of biblical books), and the surviving copies differ from one another here and there, the original wording can be determined only by comparative study of these copies. The scribal habits of individual copyists, and the remoteness of proximity to individual MSS to the original…must be investigated” (ISBE).
We do believe that the Holy Scriptures are inspired of God and that they are not myths, borrowed or copied from pagan stories or the contemporary religions around Ancient Israel. However, textual errors have occurred in the copying and transmission of the Scriptures over the centuries, be they in the Hebrew Tanach or Greek Apostolic Writings. Some of these errors were unintentional mistakes, and others may have been intentional for doctrinal reasons.
The two most commonly employed Biblical texts today that cannot be considered “critical texts,” because they have not been compared against textual discoveries, are the Masoretic Hebrew text (MT) for the Tanach and the Textus Receptus for the Greek Apostolic Writings. We use the Biblia Hebraica Stuttgartensia and the Greek New Testament, 4th Revised Edition (same as the Novum Testamentum Graece, 27th ed.), both produced by United Bible Societies. These are the same critical texts that are used in modern translations such as the Jewish Press Society Tanakh, New American Standard Bible, and the New International Version. These critical texts have the variant manuscript readings in their footnotes.
 F.F. Bruce, “Criticism,” in ISBE, 1:818.