If the internal test questioned the authors themselves, then the external test questions other observers from outside of the NT. That is, what do other sources say about the events that the Bible depicts? An eyewitness account loses credibility if it has inaccuracies in the details of the account. How does the NT stand up to scrutiny of this kind?
Imagine if three of your mortal enemies supported your alibi in a court of law. This would powerfully boost your testimony. In the same way, Roman, Greek, and Jewish sources all support the NT account of Jesus’ life.
Roman historians support the NT. Cornelius Tacitus was a Roman historian who lived from 55-117 C.E. This passage is from his book Annals, where he recounted Rome in the 60s C.E. It describes how the Roman Emperor Nero savagely persecuted Christians in Rome. Tacitus writes,
Consequently, to get rid of the report, Nero fastened the guilt and inflicted the most exquisite tortures on a class hated for their abominations, called Christians by the populace. Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilatus, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judea, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular. Accordingly, an arrest was first made of all who pleaded guilty; then, upon their information, an immense multitude was convicted, not so much of the crime of firing the city as of hatred against mankind. Mockery of every sort was added to their deaths. Covered with the skins of beasts, they were torn by dogs and perished, or were nailed to crosses, or were doomed to the flames and burnt, to serve as a nightly illumination when daylight had expired. Nero offered his gardens for the spectacle, and was exhibiting a show in the circus while he mingled with the people in the dress of a charioteer or stood aloft on a car. Hence, even for criminals who deserved extreme and exemplary punishment, there arose a feeling of compassion; for it was not, as it seemed, for the public good but rather to glut the cruelty of one man that they were being destroyed.
Greek sources support the NT. Lucian of Samosata was a second century Greek satirist (125-180 C.E.), who scorned the early Christian movement. Lucian writes,
The Christians, you know, worship a man to this day—the distinguished personage who introduced their novel rites, and was crucified on that account… You see, these misguided creatures start with the general conviction that they are immortal for all time, which explains the contempt of death and voluntary self-devotion which are so common among them; and then it was impressed on them by their original lawgiver that they are all brothers, from the moment that they are converted, and deny the gods of Greece, and worship the crucified sage, and live after his laws. All this they take quite on faith, with the result that they despise all worldly goods alike, regarding them merely as common property.
Jewish sources support the NT. The Talmud was a collection of teachings from rabbis up until 400 C.E. The Babylonian Talmud was different from the Palestinian Talmud, because it was codified in Babylon. Here is one passage that is related to Jesus:
On the eve of the Passover Yeshu was hanged. For forty days before the execution took place, a herald went forth and cried, “He is going forth to be stoned because he has practiced sorcery and enticed Israel to apostasy. Anyone who can say anything in his favour, let him come forward and plead on his behalf.” But since nothing was brought forward in his favour he was hanged on the eve of the Passover!
Even critic Bart Ehrman agrees, “There is absolutely nothing to suggest that the pagan Tacitus or the Jewish Josephus acquired their information about Jesus by reading the Gospels.”
Historians marvel at the reliability and accuracy of the book of Acts. In his book The Book of Acts in the Setting of Hellenistic History, historian Colin J. Hemer documents roughly 180 specific details about Paul’s missionary journeys, which Luke accurately recorded (Acts 13-28). These events occurred over a span of hundreds of miles from Jerusalem to Rome, and yet Luke identified all of the historical details with remarkable accuracy. Hemer calls these details “undesigned coincidences.”
Luke’s accuracy is so impressive that one of the greatest archaeologists of all time, Sir William Ramsay, came to believe in Christianity because of it. Originally, Ramsay was a hostile critic of the Bible. Early in his career, he set out on an archaeological quest to research much of Asia Minor in an effort to disprove Luke’s history, entering his archaeological research with the assumption that “Luke” had never existed. Instead, he believed that a group of Christian monks probably wrote the book of Acts in the second century.
Remarkably, after 30 years of research, Ramsay ended up becoming a Christian! He uncovered one detail after another that confirmed Luke’s account. Toward the end of his life, he concluded, “Luke’s historicity is unsurpassed in respect to its trustworthiness… Luke is a historian of the first rank; not merely are his statements of fact trustworthy… this author should be placed along with the very greatest of historians.”
How do the other “holy books” hold up to this sort of scrutiny?
When we look at other “holy books” from the other world religions, we find they do not interface with history at all, or they interface inaccurately:
Eastern scriptures really have no interest in history, because this is the world of illusion from which we are to be delivered (see “Hinduism” and “Buddhism”). Ancient polytheistic religions likewise had no interest in history. Their gods acted only in myths, removed as far as possible from real history.
The Quran is almost entirely assertions of Allah with very little historical interface.
(1) The Qur’an places the practice of crucifixion back in the time of the ancient Egyptians (7:124; 12:41; 20:71; 26:49). Historically, crucifixion wasn’t invented until the time of Darius of Persia in 519 BC.
(2) The Qur’an affirms that Mary and Miriam are the same person. The Qur’an confuses Miriam with Mary (19:28). Miriam was Moses and Aaron’s sister, while Mary is the mother of Jesus. It’s clear that the author was conflating the two people—even though there were centuries between these two figures (c.f. 3:35; 66:12). This shows Muhammad’s lack of knowledge of the Bible.
(3) The Qur’an has an aberrant understanding of the Trinity. The Qur’an reflects Muhammad’s gross misunderstanding of the Trinity—that it is composed of the Father, Jesus and Mary (5:119)! In 5:15, we read that Muhammad “expounds” on Christian doctrine. White writes, “How did Muhammad’s preaching, which shows no understanding of the content of the very Book under consideration, expound on it?”
(4) Many Muslims do not believe that Jesus died on the Cross based on Surah 4:157-158. Geisler and Saleeb write, “The great majority of Muslims believe that Jesus did not die on the cross but that he was taken up bodily into heaven.” They believe this even though non-Christian sources affirm that he did. This is why even hostile critics of the Christian faith believe that Jesus died. For instance, Gerd Lüdemann—an atheistic NT critic—explains, “Jesus’ death as a consequence of crucifixion is indisputable.” John-Dominic Crossan—a radical NT critic—concludes, “That he was crucified is as sure as anything historical can ever be, since both Josephus and Tacitus… agree with the Christian accounts on at least that basic fact.” Moreover, biblical critic Bart Ehrman writes, “One of the most certain facts of history is that Jesus was crucified on orders of the Roman prefect of Judea, Pontius Pilate.”
The Book of Mormon is fraught with historical inaccuracies. No evidence has ever been found for the historical claims of the Book of Mormon. There are a number of anachronisms and historical blunders in the Book of Mormon. A few will be considered here:
(1) Horses and Elephants: Horses (Alma 18:9, Alma 18:12, Alma 20:6, 3 Nephi 3:22) and elephants (Ether 9:19) are mentioned throughout the several thousand year history in the book of Mormon, but horses did not make it over to the Americas until the Spaniards brought them. Both of these species went extinct thousands of years before the history recorded in the book of Mormon.
(2) River Laman does not empty into the Red Sea: 1 Nephi 2:5-8 states that the river Laman emptied into the Red Sea. But there has never been any such river that emptied into the Red Sea –either in historic or prehistoric times.
(3) Christians BEFORE the time of Christ: Alma 46:15 states that believers were called “Christians” back in 73 BC—fully seven decades before Jesus was even born!
(4) Compasses existing in 73 BC: Alma 37:38 speaks of compasses, but these wouldn’t be invented for over a thousand years.
(5) The use of the word “Bible”: 2 Nephi 29:3 uses the term “Bible” and this portion of the Book of Mormon dates to the sixth century B.C. The word “Bible” comes from the Greek word biblos, which wouldn’t exist for another 1,500 years.
(6) There is no genetic similarity between the Native Americans and ancient Jews: The Book of Mormon states that Lamanites (a lost tribe of Israel) settled in America during this time, which developed into the Native Americans. However, even Mormon researchers have demonstrated that there is no genetic influence from any group from the ancient Middle East.
Mormon Thomas Stuart Ferguson spent his entire adult life trying to prove the Book of Mormon was true (Ferguson founded the New World Archaeology Foundation at BYU). At the end of his life (1975) he wrote,
With all of these great efforts, it cannot be established factually that anyone, from Joseph Smith to the present day, has put his finger on a single point of terrain that was a Book-of-Mormon geographical place. And the hemisphere has been pretty well checked out by competent people… I must agree with Dee Green, who has told us that to date there is no Book-of-Mormon geography. I, for one, would be happy if Dee were wrong.
The NT is remarkable in regards to its historical reliability. It not only stands head and shoulders above other supposed “holy books,” but it is also more reliable than any other historical document handed down to us from antiquity.
 Cornelius Tacitus Annals 15:44.
 Lucian, The Death of Peregrine, 11-13.
 Babylonian Talmud, Sanhedrin 43a.
 Ehrman, Bart D. Did Jesus Exist?: The Historical Argument for Jesus of Nazareth. New York: HarperOne, 2012. 97.
 Hemer, Colin J. The Book of Acts in the Setting of Hellenistic History. Winona Lake, IN: Eisenbrauns, 2001. 101.
 Ramsay, William Mitchell. The Bearing of Recent Discovery on the Trustworthiness of the New Testament. Grand Rapids: Baker Book House, 1953. 222. For a more modern treatment of this, see A.W. Mosley’s article titled, “Historical Reporting in the Ancient World.”
 Hoffmeier writes, “Herodotus, the fifth-century Greek historian, describes a case in which Darius the Great (522-486 BC) crucified 3,000 Babylonians.” Hoffmeier, James Karl. The Archaeology of the Bible. Oxford: Lion, 2008. 158.
 White, James R. What Every Christian Needs to Know about the Qur’an. Minneapolis, MN: Bethany House, 2013. 170.
 Geisler, Norman L., and Abdul Saleeb. Answering Islam: The Crescent in Light of the Cross. Grand Rapids, MI: Baker, 1993. 68.
 Emphasis mine. Lüdemann, Gerd. The Resurrection of Jesus: History, Experience, Theology. Minneapolis: Fortress, 1994. 50.
 Emphasis mine. Crossan, John-Dominic. Jesus: A Revolutionary Biography. Harper One. 1995. 145.
 Emphasis mine. Ehrman, Bart. The Historical Jesus: Lecture Transcript and Course Guidebook, Part 2 of 2. Chantilly, VA: The Teaching Company. 2000. 162.
 To be accurate, horses were thought to have gone extinct in the Americas at the end of the Pleistocene Era. They do not reappear until the Spanish colonized the Americas.
 Southerton, Simon. Losing a Lost Tribe: Native Americans, DNA, and the Mormon Church. Salt Lake City: Signature, 2004.
 Ferguson, “Written Symposium on Book-of-Mormon Geography: Response of Thomas S. Ferguson to the Norman & Sorenson Papers,” 4, 7, 29. Cited in Abanes, Richard. One Nation under Gods: A History of the Mormon Church. New York: Four Walls Eight Windows, 2002. 77.