We have four gospels in the New Testament, but half of them mention the Virgin Birth (Matthew and Luke), and only at the announcement of that Birth. Further, that means only two books of the 27 in the New Testament mention the Virgin Birth. There is nothing beyond Matthew and Luke in the entire New Testament pertaining to the Virgin Birth (although Galatians 4.4 might allude to in a strictly Pauline way).
This is a pivotal prophecy – one which no Messiah could do with out. Granted the Jews believe that the Hebrew means ‘young woman’ and indeed, it very well may. (Of course, what great sign from God would be a young woman with child?) Of course the Septuagint’s Translators understood Isaiah to mean ‘virgin’. Even without the prophesy in Isaiah, we have the words of God in Genesis concerning the Messiah being of the seed of a woman (Genesis 3.15). The first mention of the Messiah concerns the Virgin Birth – yet, again, it is mentioned twice in the New Testament.
This point is used by scholars and liberal theologians to attack the Virgin Birth. But what is the answer? Why, if the Virgin Birth is so important to the Messiah, is it mentioned briefly, twice, in the New Testament?
The answer is simple. The great majority of Scripture was written by the Apostle Paul. He was not writing to unbelievers, but to long-established congregations. He was writing doctrine for the Church, not to the unbelievers. It was not Luke’s job in Acts to detail to the unbelievers prophesies of Christ, as his was the history of the Church. According to Papias,
Mark having become the interpreter of Peter, wrote down accurately whatsoever he remembered. It was not, however, in exact order that he related the sayings or deeds of Christ. For he neither heard the Lord nor accompanied Him. But afterwards, as I said, he accompanied Peter, who accommodated his instructions to the necessities [of his hearers], but with no intention of giving a regular narrative of the Lord’s sayings. Wherefore Mark made no mistake in thus writing some things as he remembered them. For of one thing he took especial care, not to omit anything he had heard, and not to put anything fictitious into the statements. Matthew put together the oracles [of the Lord] in the Hebrew language, and each one interpreted them as best he could.
We find that Mark is the preachings of Peter – Mark wrote as Peter preached. (This does not line up with the scholarly ‘Q’ source, but Papias is rather old.) John wrote his gospel to fill in the gaps, which is evident by his epilogue,
And truly Jesus did many other signs in the presence of His disciples, which are not written in this book; but these are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in His name. (John 20:30-31 NKJV)
So, John wrote what the others did not, and for a purpose, to declare without a doubt the deity of Christ. He started at the very beginning (John 1.1), before the Virgin Birth, but allude to the act of the divine in the birth (John 1.14).
Matthew wrote to a community, most likely of converts and unbelievers, as did Luke. Mark was transcripts of preaching; John had a different agenda of deity. Paul wrote to established congregations, to affirm their faith and to establish a continuing doctrine for the Church as did Peter, James, and Jude. It is not mentioned by Paul because it was unnecessary to to bring up such a basic principle of Christ for those Christians who were years removed from conversion.
The Virgin Birth was not the Evangelists’ way of exploring the uniqueness of Christ, nor was it a myth conjured from surrounding paganism. The indwelling of the Virgin by the Spirit (Breath) of God is the initial sign of the coming salvation. It is a real event, meaningful to the Jews as a sign of the Messiah. It was used to show that Christ was the promised Messiah, God with us, and indeed, to the Gentiles to show that He alone fulfilled the prophesies. Once past the miracles, as with Paul, it was necessary to build up sound doctrine that relied upon Tradition and Scripture. It was not that the Virgin Birth was unknown to Paul or refuted by Paul, but it was not Paul’s mission to those congregations, to relay the foundation of the truth of Christ.