Continuing my reply to @tgGodsway:
Mary’s a virgin at Jesus’ birth, too. Matthew is speaking to Jewish converts to Christianity, and needs to defend Mary’s virginity at the time of Jesus’ birth. He needs to show that Joseph isn’t the father. And so he says, “[Joseph] had no relations with [Mary] until she bore a son.”
But wait! If he says “until”, doesn’t that mean that the story changed, afterward? If not “until”, then certainly he means that they had relations
after, doesn’t he?
No, not really. There are many examples in the Bible where we see things that happened “until” something, in which they didn’t stop happening “after”:
- “Michal the daughter of Saul had no child until the day of her death” (2 Sam 6:23). Would we say that she had a child after she died?
- “Until I come, attend to the public reading of scripture, to preaching, to teaching.” (1 Tim 4:13) Is Paul suggesting that Timothy stop reading scripture and teaching after Paul comes?
- “For [Christ] must reign until he has put all his enemies under his feet” (1 Cor 15:25). Does this mean that Christ’s reign ends after His enemies are vanquished?
So, by the same token, this verse doesn’t prove that Mary and Joseph had relations after Jesus’ birth.
But what about all those references to Jesus’ “brothers and sisters”? Don’t they
prove that Mary had other children to Joseph?
No, they don’t. The Bible is replete with mentions of people who are called “brother” or “sister” who do not share the same parents. It was common then – as it is now – to call relatives and those close to you and those with whom you share a religious bond “brother” or “sister”…
Does this prove Mary had no other children? No… but this does:
At His crucifixion, Jesus looks at Mary and the beloved disciple at the foot of the cross and says, “‘Woman, behold your son.’ Then he said to the disciple, ‘behold, your mother.’ And from that hour, the disciple took her into his home.” (John 19:26-27).
But wait! That says somethiing
very important! In that time and place, a widowed mother was expected to be taken care of by her eldest son! That role was filled by Jesus. But, at the time of his death, that obligation fell to the next oldest brother! As we read in 1 Timothy 5:3-4, “if [a widow] has children or grandchildren, their first responsibility is to show godliness at home and repay their parents by taking care of them.” This, in fact, is the standard in Jewish culture of the day. So, by telling the beloved disciple to care for Mary, Jesus is witnessing to one of two things:
- Jesus has no uterine brothers, or
- Jesus is delivering the greatest insult possible to his family: he’s giving his mother away to someone outside the family!
Given that Jesus preached “honor your mother and father” (see Mt 15:4), the latter is unthinkable. Therefore, we see that, at the time of the crucifixion, too, Jesus had no siblings.
Therefore,
from Scripture, we see that Mary was a virgin throughout Jesus’ life.