Verbal inspiration means that the process of inspiration applies to the very words used in the biblical books. It does not mean that God mechanically dictated the words of the Bible, but that those words express the thoughts that God intended, and, being correctly interpreted, are free from errors of fact, doctrine, or judgment.
The particular words do not need to be the best words to express the thought, but they must be adequate words to express the thought. In many ways the Bible claims this type of inspiration for itself… [And o]ur Savior also testifies to verbal inspiration. In several passages Jesus bases an argument on the particular wording of the OT… (Online source)