What we have concerning Jesus actually is impressive. We can start with approximately nine traditional authors of the New Testament. If we consider the critical thesis that other authors wrote the pastoral letters and such letters as Ephesians and 2 Thessalonians, we’d have an even larger number. Another twenty early Christian authors and four heretical writings mention Jesus within 150 years of his death on the cross.
Moreover, nine secular, non-Christian sources mention Jesus within the 150 years: Josephus, the Jewish historian; Tacitus, the Roman historian; Pliny the Younger, a politician of Rome; Phlegon, a freed slave who wrote histories; Lucian, the Greek satirist; Celsus, a Roman philosopher; and probably the historians Suetonius and Thallus, as well as the prisoner Mara Bar-Serapion.
In all, at least forty-two authors, nine of them secular, mention Jesus within 150 years of his death.
In comparison, let’s take a look at Julius Caesar, one of Rome’s most prominent figures. Caesar is well known for his military conquests. After his Gallic Wars, he made the famous statement, “I came, I saw, I conquered.” Only five sources report his military conquests: writings by Caesar himself, Cicero, Livy, the Salona Decree, and Appian. If Julius Caesar really made a profound impact on Roman society, why didn’t more writers of antiquity mention his great military accomplishments? No one questions whether Julius did make a tremendous impact on the Roman Empire. It is evident that he did. Yet in those 150 years after his death, more non-Christian authors alone comment on Jesus than all of the sources who mentioned Julius Caesar’s great military conquests within 150 years of his death.
-Gary Habermas and Michael Licona in The Case for the Resurrection of Jesus, Kindle Locations, 1232-1244.