Quote from : Pilgrim Theology: Core Doctrines for Christian Disciples Book

12. Historians today rely on classics like Thucydides’ History of the Peloponnesian War, Caesar’s Gallic War, and Tacitus’s Histories. The earliest copies we have for these date from 1,300, 900, and 700 years after the original writing, respectively, and there are eight extant copies of the first, ten of the second, and two of the third. In contrast, the earliest copy of Mark’s gospel is dated at AD 130 (a century after the original writing), and there are 5,000 ancient Greek copies, along with nearly 20,000 Latin and other ancient manuscripts. The sheer volume of ancient manuscripts provides sufficient comparison between copies to provide an accurate reproduction of the original text. Ironically, a number of fashionable scholars attracted to the so-called gnostic gospels as an “alternative Christianity” have far fewer manuscripts, and the original writings cannot be dated any earlier than a century after the canonical Gospels.