The Church fathers had more than the scriptures when they developed the teaching of the Church; they had the apostles and very authors of scripture to consult. In fact, the apostles appointed people who were teaching these things to leadership positions.
Catholic Answers:
Backing up the testimony of Scripture regarding Mary’s perpetual virginity is the testimony of the early Christian Church. Consider the controversy between Jerome and Helvidius, writing around 380. Helvidius first brought up the notion that the “brothers of the Lord” were children born to Mary and Joseph after Jesus’ birth. The great Scripture scholar Jerome at first declined to comment on Helvidius’ remarks because they were a “novel, wicked, and a daring affront to the faith of the whole world.” At length, though, Jerome’s friends convinced him to write a reply, which turned out to be his treatise called On the Perpetual Virginity of the Blessed Mary. He used not only the scriptural arguments given above, but cited earlier Christian writers, such as Ignatius, Polycarp, Irenaeus, and Justin Martyr. Helvidius was unable to come up with a reply, and his theory remained in disrepute and was unheard of until more recent times.
Also, on strictly Biblical grounds, Luther, Calvin, and Zwingli believed Mary, as the ark of the new covenant, was preserved in her perpetual virginity for the glory of God.
Of course, anyone can take a single verse out of context to convince you of what is not true.
Matthew 1:25
He had no relations with her until she bore a son, and he named him Jesus.
This is a perfect example. When we look at he word “until” we must not make assumptions based simply on what we have been taught by others but rather read scripture with new eyes, praying that we be guided by the Holy Spirit, and not by biases and presumptions. Saying God preserved Mary in her virginity up to the point of giving birth to Jesus is not necessarily to say God no longer preserved Mary after she gave birth to Jesus.
Consider the usage of the word “until” in this verse.
Heb 1:12-16 KJV:
12And as a vesture shalt thou fold them up, and they shall be changed: but thou art the same, and thy years shall not fail.
13But to which of the angels said he at any time, Sit on my right hand, until I make thine enemies thy footstool?
14Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?
Other translations of scripture give a clearer and more modern understanding of the word, though.
NAB:
He had no relations with her at any time before she bore a son
Knox:
He had not known her when she bore a son
That said, the entire Bible testifies to the fact that Mary had no children after Jesus. This is especially amazing if you have a good understanding of typology, as the apostles and Church fathers did. Be sure to read these verses very carefully.
Ezek 44:1-3 KJV:
1 Then He brought me back to the outer gate of the sanctuary which faces toward the east, but it was shut. 2 And the LORD said to me, “This gate shall be shut; it shall not be opened, and no man shall enter by it, because the LORD God of Israel has entered by it; therefore it shall be shut. 3 As for the prince, because he is the prince, he may sit in it to eat bread before the LORD; he shall enter by way of the vestibule of the gateway, and go out the same way.”
Luke 2:41-51 KJV:
41 His parents went to Jerusalem every year at the Feast of the Passover. 42 And when He was twelve years old, they went up to Jerusalem according to the custom of the feast. 43 When they had finished the days, as they returned, the Boy Jesus lingered behind in Jerusalem. And Joseph and His mother[a] did not know it; 44 but supposing Him to have been in the company, they went a day’s journey, and sought Him among their relatives and acquaintances. 45 So when they did not find Him, they returned to Jerusalem, seeking Him. 46 Now so it was that after three days they found Him in the temple, sitting in the midst of the teachers, both listening to them and asking them questions. 47 And all who heard Him were astonished at His understanding and answers. 48 So when they saw Him, they were amazed; and His mother said to Him, “Son, why have You done this to us? Look, Your father and I have sought You anxiously.”
49 And He said to them, “Why did you seek Me? Did you not know that I must be about My Father’s business?” 50 But they did not understand the statement which He spoke to them.
Jesus is about 12 years old and does not have any brothers or sisters mentioned or implied in this story. If he had brothers, they would be younger than him.
John 7:3–4 (KJV):
3His brethren therefore said unto him, Depart hence, and go into Judaea, that thy disciples also may see the works that thou doest.
4For there is no man that doeth any thing in secret, and he himself seeketh to be known openly. If thou do these things, shew thyself to the world.
If Jesus’ brothers are younger, they are extremely disrespectful and unorthodox.
John 19:26-27 (KJV):
26When Jesus therefore saw his mother, and the disciple standing by, whom he loved, he saith unto his mother, Woman, behold thy son!
27Then saith he to the disciple, Behold thy mother! And from that hour that disciple took her unto his own home.
If Jesus had biological brothers, it would have been illegal for him to entrust Mary to the care of his disciple. Jewish law stated that the oldest living son would take care of her.
Genesis 14:11-14 (KJV):
11And they took all the goods of Sodom and Gomorrah, and all their victuals, and went their way.
12And they took Lot, Abram’s brother’s son, who dwelt in Sodom, and his goods, and departed.
13And there came one that had escaped, and told Abram the Hebrew; for he dwelt in the plain of Mamre the Amorite, brother of Eshcol, and brother of Aner: and these were confederate with Abram.
14And when Abram heard that his brother was taken captive, he armed his trained servants, born in his own house, three hundred and eighteen, and pursued them unto Dan.
Obviously, Lot was not Abram’s literal brother.
Luke 1:34 (KJV):
34Then said Mary unto the angel, How shall this be, seeing I know not a man?
Catholic Answers:
Mary knew how babies are made …]. If she had anticipated having children in the normal way …] she would hardly have to ask “how” she was to have a child, since conceiving a child in the “normal” way would be expected by a newlywed wife.
For 1,600 years Christianity taught Mary remained a virgin. After that, some people said otherwise. The burden of proof is on them. I have seen none that is conclusive.
