Here is part of an article that is from the main site: http://www.godandscience.org/apologetic ... rigin.html I reformatted the outline slightly.
"Skeptics and liberal Christian scholars both seek to date the New Testament books as late first century or early second century writings. They contend that these books were not written by eyewitnesses but rather by second or third hand sources. This allowed for the development of what they view as myths concerning Jesus. For example, they would deny that Jesus actually foretold the destruction of Jerusalem. Rather they would contend that later Christian writers "put these words into his mouth."
1. Many of the New Testament books claim to be written by eyewitnesses.
A. The Gospel of John claims to be written by the disciple of the Lord. Recent archeological research has confirmed both the existence of the Pool of Bethesda and that it had five porticoes as described in John 5:2. This correct reference to an incidental detail lends credibility to the claim that the Gospel of John was written by John who as an eyewitness knew Jerusalem before it was destroyed in 70 A. D.
A. Paul signed his epistles with his own hand. He was writing to churches who knew him. These churches were able to authenticate that these epistles had come from his hands (Galatians 6:11). Clement an associate of Paul's wrote to the Corinthian Church in 97 A. D. urging them to heed the epistle that Paul had sent them.
2. The following facts strongly suggest that both the Gospel of Luke and the Book of Acts were written prior to 65 A.D. This lends credibility to the author's (Luke) claim to be an eyewitness to Paul's missionary journeys. This would date Mark prior to 65 A.D. and the Pauline epistles between 49-63 A.D.
A. Acts records the beginning history of the church with persecutions and martyrdoms being mentioned repeatedly. Three men; Peter, Paul, and James the brother of Jesus all play leading roles throughout the book. They were all martyred by 67 A.D., but their martyrdoms are not recorded in Acts.
B. The church in Jerusalem played a central role in the Book of Acts, but the destruction of the city in 70 A.D. was not mentioned. The Jewish historian Josephus cited the siege and destruction of Jerusalem as befalling the Jews because of their unjust killing of James the brother of Jesus.
3. The Book of Acts ends with Paul in Rome under house arrest in 62 A.D. In 64 A.D., Nero blamed and persecuted the Christians for the fire that burned down the city of Rome. Paul himself was martyred by 65 A.D. in Rome. Again, neither the terrible persecution of the Christians in Rome nor Paul's martyrdom are mentioned.
Conclusion: These books, Luke-Acts, were written while Luke was an eyewitness to many of the events, and had opportunity to research portions that he was not an eyewitness to.
The church fathers bear witness to even earlier New Testament manuscripts
The earliest manuscripts we have of major portions of the New Testament are p 45, p 46, p66, and p 75, and they date from 175-250 A. D. The early church fathers (97-180 A.D.) bear witness to even earlier New Testament manuscripts by quoting from all but one of the New Testament books. They are also in the position to authenticate those books, written by the apostles or their close associates, from later books such as the gospel of Thomas that claimed to have been written by the apostles, but were not.
1. Clement (30-100 A.D.) wrote an epistle to the Corinthian Church around 97 A.D. He reminded them to heed the epistle that Paul had written to them years before. Recall that Clement had labored with Paul (Philippians 4:3). He quoted from the following New Testament books: Luke, Acts, Romans, 1 Corinthians, Ephesians, Titus, 1 and 2 Peter, Hebrews, and James.
2. The apostolic fathers Ignatius (30-107 A.D.), Polycarp (65-155 A.D.), and Papias (70-155 A.D.) cite verses from every New Testament book except 2 and 3 John. They thereby authenticated nearly the entire New Testament. Both Ignatius and Polycarp were disciples of the apostle John.
3. Justin Martyr, (110-165 A.D.), cited verses from the following 13 books of the New Testament: Matthew, Mark, Luke, John, Acts, Romans, 1 Corinthians, Galatians, 2 Thessalonians, Hebrews, 1 and 2 Peter, and Revelation.
4. Irenaeus, (120-202 A.D.), wrote a five volume work Against Heresies in which,
A. He quoted from every book of the New Testament but 3 John.
B. He quoted from the New Testament books over 1,200 times.
How was the New Testament canon determined?
The Early church had three criteria for determining what books were to be included or excluded from the Canon of the New Testament.
1. First, the books must have apostolic authority-- that is, they must have been written either by the apostles themselves, who were eyewitnesses to what they wrote about, or by associates of the apostles.
2. Second, there was the criterion of conformity to what was called the "rule of faith." In other words, was the document congruent with the basic Christian tradition that the church recognized as normative.
3. Third, there was the criterion of whether a document had enjoyed continuous acceptance and usage by the church at large.
4. The gospel of Thomas is not included in the Canon of the New Testament for the following reasons.
A. The gospel of Thomas fails the test of Apostolic authority. None of the early church fathers from Clement to Irenaeus ever quoted from the gospel of Thomas. This indicates that they either did not know of it or that they rejected it as spurious. In either case, the early church fathers fail to support the gospel of Thomas' claim to have been written by the apostle. It was believed to by written around 140 A.D. There is no evidence to support its purported claim to be written by the Apostle Thomas himself.
B. The gospel of Thomas fails to conform to the rule of faith. It purports to contain 114 "secret sayings" of Jesus. Some of these are very similar to the sayings of Jesus recorded in the Four Gospels. For example the gospel of Thomas quotes Jesus as saying, "A city built on a high hill cannot be hidden." This reads the same as Matthew's Gospel except that high is added. But Thomas claims that Jesus said, "Split wood; I am there. Lift up a stone, and you will find me there." That concept is pantheistic. Thomas ends with the following saying that denies women salvation unless they are some how changed into being a man. "Let Mary go away from us, because women are not worthy of life." Jesus is quoted as saying, "Lo, I shall lead her in order to make her male, so that she too may become a living spirit, resembling you males. For every woman who makes herself male will enter into the kingdom of heaven."
C. The gospel of Thomas fails the test of continuous usage and acceptance. The lack of manuscript evidence plus the failure of the early church fathers to quote from it or recognize it shows that it was not used or accepted in the early Church. Only two manuscripts are known of this "gospel." Until 1945 only a single fifth-century copy translation in Coptic had been found. Then in 1945 a Greek manuscript of the Gospel of Thomas was found at Nag Hammadi in Egypt. This compares very poorly to the thousands of manuscripts that authenticate the Four Gospels."