The case for the historical reliability of the New Testament
does not rest only on the New Testament itself. Several ancient
sources outside the Bible mention Jesus and early Christianity,
and their accounts are consistent with what the New Testament
records.
Tacitus, a Roman historian writing around 116 AD, records that
Christ was executed by Pontius Pilate during the reign of
Tiberius and that his followers spread throughout the Roman
empire. Tacitus had no sympathy for Christianity. He describes
it as a destructive superstition. That makes his confirmation
of the basic historical facts more significant, not less.
Josephus, a Jewish historian writing in 93 AD, refers to
James as "the brother of Jesus who was called Christ" and in a
separate passage describes Jesus as a wise man who performed
surprising works and was condemned by Pilate. Josephus was not
a Christian and was writing for a Roman audience. His
references to Jesus are not the testimony of a believer.
Pliny the Younger, a Roman governor writing around 112 AD,
describes Christians worshipping Christ as a god and refusing
to recant even under threat of execution. This confirms both
the early date of Christian devotion to Jesus and the
seriousness with which his followers held their convictions.
None of these sources prove everything the New Testament
claims. But they do confirm that Jesus was a real historical
figure, that he was crucified under Pontius Pilate, and that
his followers were making extraordinary claims about him within
a generation of his death.