“How will this be.” Mary’s question is legitimate. In fact, it seems as if the angel intentionally did not include the part about the virgin birth in what he first told Mary about giving birth to the Messiah so that his message could be in two parts. For Mary to take in that she would be the mother of the Messiah would have been plenty to ponder, but then to come to realize that she would be pregnant as a virgin…how would she explain that to anyone?
It shows the quick mind of Mary, and her self-confidence, that she would ask the angel how she would get pregnant. Many people would freeze up in the presence of an angel and not be able to think of anything to say, but Mary grasped the situation and what the angel was telling her, and asked how she could give birth without being married.
“I am not knowing a man.” Mary believed from the Old Testament text that the Messiah would be a man who was born of a woman, and now the angel said that woman would be her. Since the virgin birth was not set forth clearly in the Old Testament (see commentary on Isa. 7:14), Mary assumed that she would have to be married and having sex with a man in order to conceive the Messiah, thus her statement, “I am not knowing [sexually] a man.” As it turned out, the angel revealed that God would contribute the sperm (via creation) that impregnated Mary. Although many Christians believe that Jesus Christ was “incarnated” into the flesh, in other words, placed in Mary as a complete baby at some form of development, the Bible never says that and that is not what happened. The Bible makes the case that Mary was the true mother of Jesus Christ, not just a surrogate mother for God. Jesus could not have been a true descendant of David if there were no actual genetic link to the line of David. Furthermore, what would be the point of the genealogy in Matthew? If God simply had Mary “carry” Jesus, then his only genealogy is 100% from God, not at all from David. In fact, that Jesus Christ is an actual descendant of David is one of the pieces of evidence that he is not God. The link between Mary and Jesus in Matthew 1:16 would not be a genetic link at all. God is not a descendant of David, and a descendant of David cannot be God.
[For more on why Mary was not expecting a virgin birth, see commentary on Matt. 1:23 and Isaiah 7:14. For more on the word “know” being an idiom for sexual intercourse, see commentary on Matt. 1:25. For more on Jesus Christ being the Son of God and not “God the Son,” see Appendix 10, “Jesus is the Son of God, Not God the Son.”]