2. I must call upon the Holy Spirit to express His meaning by my mouth and defend the virginity of the Blessed Mary. I must call upon the Lord Jesus to guard the sacred lodging of the womb in which He abode for ten months from all suspicion of sexual intercourse. And I must also entreat God the Father to show that the mother of His Son, who was a mother before she was a bride, continued a Virgin after her son was born. We have no desire to career over the fields of eloquence, we do not resort to the snares of the logicians or the thickets of Aristotle. We shall adduce the actual words of Scripture. Let him be refuted by the same proofs which he employed against us, so that he may see that it was possible for him to read what is written, and yet to be unable to discern the established conclusion of a sound faith.While we agree with Jerome that the standard should be the actual words of Scripture and not attempts at Aristotelean philosophy, we have to note that Jerome is still not actually setting forth a valid argument for his position.
Notice that Jerome seems to think that "sexual intercourse" is something bad. Thus, he describes suggestions to the contrary of his position as "suspicion of sexual intercourse" like one might speak of "suspicion of fornication" or the like.
Here is an opportunity, however, to help define the difference between us. We agree that Mary was a virgin before the conception of Christ, and that until Jesus was born she remained a virgin. This is important, not because virginity itself is somehow sacred, but because it was necessary that it be clear that Jesus was the Son of God.
Upon Jesus' birth, the need for Mary to remain a virgin ceased.
Likewise, Mary was already betrothed when she was found with child. She was Joseph's bride-to-be, though they had not yet come together. Under the Jewish regime, it would have been adultery for her to have been sexually joined to anyone but Joseph ("If a damsel that is a virgin be betrothed unto an husband, and a man find her in the city, and lie with her; Then ye shall bring them both out unto the gate of that city, and ye shall stone them with stones that they die; the damsel, because she cried not, being in the city; and the man, because he hath humbled his neighbour's wife: so thou shalt put away evil from among you." Deuteronomy 22:23-24), and when Joseph discovered her pregnancy, he was planning to divorce her ("Then Joseph her husband, being a just man, and not willing to make her a publick example, was minded to put her away privily." Matthew 1:19).
That stood in contrast to the situation of a virgin that was not betrothed (Exodus 22:16 And if a man entice a maid that is not betrothed, and lie with her, he shall surely endow her to be his wife.). In that situation, neither death nor merciful divorce (as Joseph thought he would do) was appropriate. Instead, in that case, the seduced girl would (with her father's permission) become the spouse of the seducer.
Joseph was not minded to track down her seducer and make him marry Mary, he was minded to "put away" (i.e. divorce) Mary. This demonstrates that Mary was to be Joseph's wife.
Moreover, when Joseph considered this option of putting away Mary, God intervened.
Matthew 1:20 But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost.
Look at that! God specifically tells Joseph not to be afraid to take Mary unto him. In context, that means Joseph is not to be afraid to take Mary to be his wife, which will involve the very thing that so troubled our ancient brother Jerome. After all, that's what distinguishes husband and wife from merely "betrothed" and is what is involved in "taking" her (compare "And what man is there that hath betrothed a wife, and hath not taken her? let him go and return unto his house, lest he die in the battle, and another man take her." Deuteronomy 20:7).
In fact, it is such an integral part of taking her, that the Scriptures make sure to explain an exception:
Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife: and knew her not till she had brought forth her firstborn son: and he called his name JESUS.
Notice that Joseph took Mary to be his wife, but did not know her until Jesus was born. The implication, of course, is that this exceptional case ended with the identified terminus, namely Jesus' birth.