“Look, the young woman is with child and shall bear a son” -Isaiah
Two errors were made when this passage was translated into Greek for the Septuagint. First "young woman" was translated to "virgin" and secondly the tense of the sentence was translated from present tense to future tense.
“The virgin will be with child and will give birth to a son” -Matthew
Philo, a prolific Jewish writer who lived from 20 BCE to 50 CE, wrote extensively about the political and theological movements throughout the Mediterranean, and his views foreshadowed Christian theology, yet he never once wrote anything about Jesus. Not only this, but he actually wrote about political conflicts between the Jews and Pontius Pilate in Judea
“Titus Flavius Josephus (37 – c. 100), was a 1st-century Romano-Jewish historian and hagiographer of priestly and royal ancestry who recorded Jewish history, with special emphasis on the 1st century AD and the First Jewish–Roman War"
Was a Jew who did not believe in the Godhood of Jesus, but acknowledged his existence in the day.
The normal objective measure of the reliability of historical documents is: 1) The number of available copies of ancient manuscripts and 2) the time span between the original version and the date of those copies still in existence today. When examined under this standard, the Bible proves to provide a treasure trove of proof and evidence that Jesus really existed.
There are important points on each side of this debate, and its important to understand that neither side is ignorant, and both sides have fair points. Obviously this is an important aspect of Christianity, and there are many reasons to support it.