The Annunciation is chronicled in the Gospel of Luke, and — along with the wedding at Cana — gives us the best glimpse into just who Mary was. For those who might be interested, it should be noted that the first half of the Hail Mary prayer is derived directly from Luke 1.

In the section concerning Mary as the New Ark, we looked at Mary's visit to Elizabeth, and at how the yet-unborn John the Baptist leapt in Elizabeth's womb at the sound of Mary's voice. This, of course, paralleled David's leaping and shouting before the Ark of the Covenant, and is a part of Luke's confirmation that Mary herself is the New Ark of the Covenant. Prior to this incident, though, is the actual Annunciation, when the angel Gabriel appeared to Mary and told her of God's plan.

Let's look closely at the Luke's detail of the Annunciation.

[26]In the sixth month the angel Gabriel was sent from God to a city of Galilee named Nazareth,

[27] to a virgin betrothed to a man whose name was Joseph, of the house of David; and the virgin's name was Mary.

Notice here the rather profound significance that Luke gives to Mary's virginity — two mentions of it in a single verse. This could just be an attempt to give attention to the prophecy concerning the virgin who would conceive and bear a son, but it should be noted that even a goodly number of Jewish scholars note that the relevant passage from Isaiah is more properly translated as "the young woman shall conceive…"

That's not to say that Isaiah was not referring to Mary, of course; he was. The point is that the emphasis on Mary's virginity is significant above and beyond its relevance to prophecy. Luke is drawing our attention to it.

[28] And he came to her and said, "Hail, O favored one, the Lord is with you!"

This is an off topic observation, but I might note that a slightly different translation of this greeting is basically the first like of the Hail Mary. "O favored one" is often translated as "full of grace". The Greek term used is kecharitomene, which is always used as a description of a characteristic quality of a person, and its use here is an implication on the part of Luke that Mary was in a state of sanctifying grace at least at the time of the Annunciation (that is: prior to her being overshadowed by the Spirit), and possibly from the very beginning.

[29] But she was greatly troubled at the saying, and considered in her mind what sort of greeting this might be.
[30] And the angel said to her, "Do not be afraid, Mary, for you have found favor with God.
[31] And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus.
[32] He will be great, and will be called the Son of the Most High;
and the Lord God will give to him the throne of his father David,
[33] and he will reign over the house of Jacob for ever;
and of his kingdom there will be no end."
[34] And Mary said to the angel, "How shall this be, since I have no husband?"

Luke 1:34 is the most significant line here, for a variety of reasons. First, it should be noted that the line has been translated in a variety of ways. The King James Version, for example, puts the line as follows: "Then said Mary unto the angel, How shall this be, seeing I know not a man?" Other translations end her question with "since I am a virgin." We've already discussed the concept of "know" as it is used in different parts of the Bible; I trust the meaning here is likewise understood by the Reader.

Now, let's pause and consider something: why did Mary respond in this way?

Mary was betrothed to Joseph — we are told this directly. She was to be married to him in short order, although they had not dwelt in the same house at the time she conceived Christ — this is confirmed by the Gospel of Matthew (c.f. Matthew 1:18). Now, correct me if I am wrong, but if I walked up to a blue-eyed bride and remarked to her that her kids are probably going to have nice blue eyes as well, her response would probably not be "how can this be?" Indeed, if you were to talk to most brides, they probably wouldn't express surprise if you noted that somewhere along the line there might be a baby or two that gets born.

And if any bride did respond with incredulity, what would that mean? Well, in our modern era, it probably means that either she has no idea what sex is, or that she and her husband have decided to make heavy use of various birth control methods. In the past, though, it could have either meant that the bride was indeed in need of a bit of a talking-to regarding "the birds and the bees", or that she had elected to remain celibate even into marriage.

We've already covered how Jewish law allowed for just such an undertaking — that is, how it allowed for a young woman to take a vow of celibacy that her husband would have implicitly assented to if he did not object within the day he learned of the vow. We have likewise covered, O Reader, how if the husband were to withdraw his approval of the vow after that first day, the sin of breaking a promise to the Lord would not be upon the wife: it would be upon the husband. Joseph, being a righteous man, would certainly have been cognizant of this fact, and would not have acted to bring about an occasion of sin for either himself or his wife, if in fact Mary had taken such a vow.

Scripture does not explicitly confirm that she had made just such a vow, of course, but — in noting that point — we still have to come back to her response to the angel. Indeed, if we look at it in context, we note that of the two possible explanations for her incredulity (ignorance regarding sex & reproduction vs. vow of celibacy), only the explanation that she had taken a vow of celibacy makes sense.

Regardless of the translation, the nature of Mary's response in Luke 1:34 confirms, at least, that she knows a thing or two about "the birds and the bees" — she understands that children are a natural result of sex. And even if somehow she did not understand sexuality to that extent, the angel spells it out plainly for her (c.f. Luke 1:31). So we can safely discard the possibility that Mary had absolutely no knowledge concerning the functional aspects of reproduction.

And if we assume that Mary was an observant Jew — that is, that she had found favour with the Lord in part due to her diligent (c.f. Deuteronomy 6:17) observation of the extant covenant between God and man — and that she was even partly aware of the tenets of the law of Moses, we can certainly assume that she knew what sex was, and what it was for. Mosaic law is full of ordinances concerning sexuality, after all.

So the only explanation for Mary's incredulous response that makes sense at all is that she had intended to live out her days under a vow of perpetual virginity.

Possible Objection #3: what about Matthew 1:24-25? It says very clearly that Joseph took Mary as his wife, "but knew her not until she had borne a son." This completely confirms that they must have had sex after the birth of Jesus.

Response to Objection #3: the Greek word that is translated as "until", heos, does not always imply a reversal. Consider its use in Matthew 28:20:

And behold, I am with you always, until the end of the age.

Are we to infer, then, that Jesus will not be with us after the end of the age? Of course not…but if we are to be consistent in our interpretation of Scripture, we should take care and make sure that when we interpret Matthew's earlier description of the state of marital relations between Mary and Joseph, we do not interpret the verse in a way that we would not dare use to interpret a later verse in the same Gospel account.

Possible Objection #4: but in Matthew 1:25, the term used is heos hou. This is a different phrasing than in Matthew 28:20. It must imply a reversal.

Response to Objection #4: actually, it doesn't; it is, as Clay Randall notes, "a Koine Greek shorthand for the phrase heos hou chronou en hoi (translated "until the time when") and both phrases do not always mean a reversal of the condition being described in the main clause; for example:

"And when Paul appealed that he be held in custody for the Emperor's decision, I ordered him held until I could send him to Caesar" (Acts 25:21)

Does this mean that Paul was no longer in custody by the time he was sent to Caesar? No.

Consider Matthew 13:33, "the kingdom of heaven is like yeast that a woman took and mixed with three measures of wheat flour until the whole batch was leavened" Does this mean that once the batch was leavened, the woman removed the yeast? Of course not."

Randall also provides a list of other passages of Scripture in which "until" is used in a non-reversing manner: "Genesis 8:7, 26:13, Numbers 20:17, Deuteronomy 2:15, 34:6, 2 Kings 6:25, 1 Chronicles 6:32, 2 Chronicles 21:15, 2 Chronicles 26:15, Judith 14:8, Judith 15:5, Tobit 2:4, Psalm 57:1, Psalm 72:7, Psalm 110:1, Psalm 123:2, Psalm 141:10, Psalm 142:7, Ecclesiastes 2:3, Song of Solomon 1:12, 2 Samuel 6:23, Isaiah 14:2, 33:23, Ezekiel 24:13, 1 Maccabees 5:54, Matthew 13:33, Matthew 14:22, Matthew 16:28, Matthew 18:34, Matthew 26:36, Matthew 28:20, John 4:49, Romans 8:22, 1 Corinthians 4:5, 1 Corinthians 15:25, Ephesians 4:13, 1 Timothy 4:13, 1 Timothy 6:14, 2 Peter 1:19, Revelation 2:25-26."

And since what is at really under discussion here is a Greek phrase, then if we look at the Septuagint we can note that in the Old Testament, the following passages feature an example of heos hou specifically, in which it is used in a non-reversing manner: "Genesis 26:13, Deuteronomy 2:15, 2 Kings 6:25, 1 Chronicles 6:32, 2 Chronicles 21:15, 2 Chronicles 26:15, Judith 14:8, Judith 15:5, Tobit 2:4, Tobit 2:5, Psalm 57:1, Psalm 72:7, Psalm 123:2, Psalm 141:10, Psalm 142:7, Ecclesiastes 2:3, Song of Solomon 1:12, Isaiah 33:23, Ezekiel 24:13."

Now, as the Reader can see, we are beginning to jump all over the Bible here. This, then, gives us a very natural entrance into the next part of our discussion: how Mary is referenced in the rest of the Gospels, and how these other references pertain to her perpetual virginity.