What is the scriptural evidence that Mary was always a virgin?

In those days, the fault of a married couple not having children, was attributed to the wife, and not to the husband.See God promising Abraham at Gen 17:16: " I will bless her, and moreover I will give you a son by her. I will bless her, and she shall give rise to nations; kings of peoples shall come from her.”

Now, Evangelist Matthew at 1:25 makes the statement : ""But he (Joseph) had no marital relations with her(Mary) until she had borne a son " . We could, for the sake of academic interest, construct an elucidation from Matthew in his own words, on the following lines:

(A) Mary proved herself that she could be a biological mother by conceiving and giving birth to baby Jesus.(B) A basic knowledge of biology tell us that one cannot impregnate a woman who is already pregnant, with a subsequent child (C) Joseph, like every man around, was capable of producing children provided his wife was not barren. (D) If Joseph remained a celibate till the birth of Jesus and reclaimed his rights as the legally married husband of Mary thereafter, they would have more children, which you my readers, don't see around. My friend John has already written how Jesus, just before his death on the cross, entrusted Mary's care to John who took her to his home( for the rest of her life).

That said, Mtt 1:25, if interpreted in the right perspective, would go a long way in postulating that Blessed Mother Mary remained a virgin throughout her life. After all, there is nothing superhuman if Joseph and Mary vowed for a life of celibacy after the conception and birth of Jesus. Incidentally, virginity may not have been considered a highly regarded virtue for lay people in those days, to the level as it is today, especially for the Catholic religious people. Hence the short statement of Matthew .

1. There is no mention of any siblings in the flight to Egypt, the return from Egypt or the visit to the temple when Jesus was about 12. Thus any children of Mary beside Jesus would be at least thirteen years younger than him, hence twenty or younger at his Crucifixion.

2. At the cross, Jesus tells John to behold his mother, and to Mary, to behold her son. Thereafter, John took her into his home. A reason given for this by some Protestant apologists is that Jesus’ siblings were not saved, and he wanted to leave his mother in the care of a believer. However, Jesus appeared to James “the brother of Jesus” before his ascension, hence only days later. This James then became a leader of the church in Jerusalem, as attested in Acts and by Paul. If this James, given at the head of the list of Jesus’ siblings, hence likely the eldest, would soon become a believer and later a martyr, assigning John the task of caring for his mother would not make sense. Culturally, the responsibility to care for your mother after your father died would fall on the eldest son. If on top of that, the eldest remaining son became mature enough to write one of the books of the Bible and lead the church, there would be no need to change living arrangements.

Historically, certain members of the church would spiritually argue from Ezekiel's vision of the temple and apply it to Mary and Jesus' birth; that is, Mary remained a virgin even in the act of giving birth and of course thereafter.

They would argue biblically from the metaphor of the king leaving the temple via the east gate and no one returning.

Now when the prince shall prepare a voluntary burnt offering or peace offerings voluntarily unto the LORD, one shall then open him the gate that looketh toward the east, and he shall prepare his burnt offering and his peace offerings, as he did on the sabbath day: then he shall go forth; and after his going forth one shall shut the gate. Eze 46:12

The prince refers to Jesus who voluntarily gave of Himself. He would come forth out of the temple (Mary's womb) through the east gate (her side, not the "south gate"). Thereafter, the gate would be shut.

This belief lasted centuries, even to John of Damascus who taught circa 750 CE.

The conception [of Jesus], indeed, was through the sense of hearing, but the birth through the usual path by which children come, although some tell tales of His birth through the side of the Mother of God. For it was not impossible for Him to have come by this gate, without injuring her seal in anyway. John Damascus-source

"Not impossible" implies it was a well known and strongly supported idea that Jesus was born from her "east gate".

As to the virgin conceiving, the Isaiah 7:14 prophecy is used.

Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.

So, the Biblical basis used to prove Mary's virginity before birth was the Isaiah prophecy , during birth and after birth was the Ezekiel prophecy.

PS EDIT TO ADD

On the assertion that because Jesus appointed John son of Zebedee as "son" to Mary, rather than to her other biological sons, as proof of her ongoing virginity, there are other more reasonable explanations.

At the time of the cross, all of His possible biological brothers and sisters had abandoned Jesus. John, however, along with Mary were at the cross.

Jesus knew John would survive longer than any of the others.

The Zebedee's were probably first cousins of Mary (see also here).

So, Jesus appointing John as son and Mary as his mother appears very natural, rather than as a proof of ongoing virginity.

The Biblical argument for the perpetual virginity of Mary are quite solid, they just require a more-than-surface level reading of the text, and a little Scripture knowledge, to make sense of.

"I Know Not Man"

First, we have the fact that Mary herself says "I know not man" (Luke 1:34) when Gabriel tells her she will "concieve and bear a son." This might not seem like a powerful argument (or even an argument at all) unless we understand what Mary is saying.

"To know" is a Hebrew euphemism meaning "to have sexual relations." E.g., "Adam knew Eve his wife, and she conceived and bore a son" (Genesis 4:1). "A young girl with a very comely appearance — a virgin whom no man had known." (Genesis 24:16). So Mary is literally saying, by use of a euphemism, "How shall I conceive, given the fact that I do not have sexual relations?"

This is significant because she was already betrothed to Joseph (Luke 1:27). If she had intended to have children with Joseph according to the ordinary manner, she wouldn't have brought up her not knowing man as an obstacle to conception, because it wouldn't exist, and she would already know the means of conception, and it would precisely be by 'knowing man.' This is why the translation, "I am a virgin" is misleading, and, frankly, wrong: a married woman who intends to have children with her spouse doesn't ask how she will have children if she is a virgin.

This alone is proof, considering that 'I can't have a baby, since I don't have sex, so how is this going to work' is pretty explicit, but there is another subtle clue in another Scripture.

The "Humiliation" of the Maidservant of God

Another more subtle proof is something Mary says in her Magnificat:

Luke 1:46-55...My soul doth magnify the Lord. 47 And my spirit hath rejoiced in God my Saviour. 48 For he hath looked upon the affliction of his handmaid; for behold from henceforth all generations shall call me blessed. 49 Because he that is mighty, hath done great things to me; and holy is his name. 50 And his mercy is from generation unto generations, to them that fear him. 51 He hath shewed might in his arm: he hath scattered the proud in the conceit of their heart. 52 He hath put down the mighty from their seat, and hath exalted the humble. 53 He hath filled the hungry with good things; and the rich he hath sent empty away. 54 He hath received Israel his servant, being mindful of his mercy: 55 As he spoke to our fathers, to Abraham and to his seed for ever.

(To those reading the Douay-Rheims, they will see "humility." However, the original word, including the Latin of which it is a translation, means "humiliation" or "shame" or "afflication" or "debas*m*nt" depending on context.)

This comes from Semitic culture, where inability to conceive children was viewed as a veritable curse from God (the opposite, that is, to the blessing of being given children), and thus termed it their "affliction" or "humiliation" when they were barren and could not have children.

Genesis 29:32 And the Lord seeing that [Jacob] hated Leah, opened her womb, but her sister remained barren. And she conceived and bore a son, and called his name Reuben, saying: The Lord hath looked upon my affliction: now my husband will love me.

1 Samuel 1:8-11 And Elkanah her husband said to Hannah: Why dost thou weep? And why dost thou not eat? And why is thy heart sorrowful? Am I not better in thy eyes than ten sons? . . . And she made a vow, saying: Lord of hosts, If thou wilt look indeed upon the humiliation of your handmaid, and remember me, and forget not thy handmaid, but give thy handmaid offspring, I will dedicate him to the Lord for all the days of his life, and a razor shall never touch his head.¹ . . . And Eli [the priest] answered, Go in peace, may the God of Israel give thee thee what it is thou hast asked of him. And she [Hannah] said: May thy handmaid find favor in thy eyes.

Cf. Genesis 41:52

This is Mary saying, "The Lord gave me children in spite of my not being able to have children naturally!" Not only does this explain why Mary mentions the Lord taking away the otherwise utterly unexplained "humilation of" Mary, which would thus be explained, but also explains several other things. First, when Gabriel says, "Fear not Mary, for thou hast found favor with God," this in context, might mean, "God has heard your prayers for children despite being a virgin for life," and explains the greeting of Gabriel: "Hail, Κεχαριτωμενη." Κεχαριτομενη is the Greek translation of the name Hannah. A probably theory might be that Luke, who makes many allusions to the Old Testament apparently deliberately, especially the books of Samuel, might be reducing the Semitic original behind "kecharitomene" to "graced" in order to direct us to this allusion deliberately (since "kecharitomene" cannot have a direct Semitic equivalent, but must be multiple words in the original Hebrew or Aramaic).

Taken as a package, this is all an allusion to this barrenness-humilitation being taken away by God who looks on this afflication and the subject finding grace in his eyes. The humiliation in question being unable to conceive children due to natural inability - or in Mary's case, a vow of virginity of some kind, or as tradition has it, herself being dedicated to the Temple and thus sacred.

Moreover, they both break into prayer in a similar fashion:

1 Samuel 2:1-10

My heart hath rejoiced in the Lord, and my horn is exalted in my God: my mouth is enlarged over my enemies: because I have joyed in thy salvation. 2 There is none holy as the Lord is: for there is no other beside thee, and there is none strong like our God. 3 Do not multiply to speak lofty things, boasting: let old matters depart from your mouth: for the Lord is a God of all knowledge, and to him are thoughts prepared. 4 The bow of the mighty is overcome, and the weak are girt with strength. 5 They that were full before have hired out themselves for bread: and the hungry are filled, so that the barren hath borne many: and she that had many children is weakened. 6 The Lord killeth and maketh alive, he bringeth down to hell and bringeth back again. 7 The Lord maketh poor and maketh rich, he humbleth and he exalteth. 8 He raiseth up the needy from the dust, and lifteth up the poor from the dunghill: that he may sit with princes, and hold the throne of glory. For the poles of the earth are the Lord's, and upon them he hath set the world. 9 He will keep the feet of his saints, and the wicked shall be silent in darkness, because no man shall prevail by his own strength. 10 The adversaries of the Lord shall fear him: and upon them shall he thunder in the heavens. The Lord shall judge the ends of the earth, and he shall give empire to his king, and shall exalt the horn of his Christ.

Luke 1:46-55

My soul doth magnify the Lord. 47 And my spirit hath rejoiced in God my Saviour. 48 Because he hath looked upon the humiliation of his handmaid; for behold from henceforth all generations shall call me blessed. 49 Because he that is mighty, hath done great things for me; and holy is his name. 50 And his mercy is from generation unto generations, to them that fear him. 51 He hath shewed might in his arm: he hath scattered the proud in the conceit of their heart. 52 He hath put down the mighty from their seat, and hath exalted the humble. 53 He hath filled the hungry with good things; and the rich he hath sent empty away. 54 He hath received Israel his servant, being mindful of his mercy: 55 As he spoke to our fathers, to Abraham and to his seed for ever.

The Brothers of Jesus

The argument that Jesus had brothers, and that thus these are sons of Mary, takes a back seat to the Luke 1:34 evidence, since it is more explicitly about Mary's sexual activity or lack thereof, whereas "Jesus' brothers" could mean more than one thing in Semitic usage, as several Scriptures and other Hebrew and Aramaic texts show. It could be that these are sons of Joseph by a prior marriage, or simply relatives of Jesus.

That is, if these show Mary intended not to have children with Joseph, then the brothers of Jesus must refer to the relatives of Jesus, and thus cannot be used as explicit evidence: "I don't have sex" is more explicit than "the brothers of Jesus." It would be backward to consider the evidence the other way around, considering first verses less explicitly about Mary, and her virginity, and instead about Jesus' brothers which, in contrast, are ambiguous.

^Footnotes

^{1 The Nazarite vow — the equivalent of monks in the Old Testament period.}

There is not a passage in the bible which states this explicitly, but certain passages do support the idea. Most notably, the Apostle John took Mary into his home to care for her as her son after Christ's death (John 19:26-27). This would have been unnecessary, and indeed quite odd, if Jesus had other brothers. One could make the argument that Jesus did not want any of His brothers caring for their mother because they were all wicked men who did not follow Him, but Protestants often point out that there is an Apostle named James, who is often called the brother of Jesus. This, they say, is evidence that Mary had subsequent children after Jesus.

James, while he fled the crucifixion, was not wicked. He was an Apostle, and he along with all the others beside Judas repented, went on to evangelize the world, and eventually was martyred. Jesus obviously would have known on the cross that James would be the appropriate man to care for their mother, Mary, if he were actually James' biological brother. What reason could Christ have had for abdicating James of his filial responsibility under the 4th commandment (thou shalt honor thy mother and thy father) and burdening John with that responsibility instead. Protestants who wish to claim that James is the biological brother of Jesus, that he is a biological son of the Virgin Mary, need to answer this question. This would also have been shameful for James, to allow another man who was not his own mother's son to care for her in his stead when he was perfectly capable of doing so himself.

To reiterate, it would indeed be very strange for Jesus to take the responsibility of the care for His mother away from His biological brothers, who have that duty already, and to ask John to take that duty on instead. Therefore, it seems unlikely, given this story from the cross, that Mary had other children besides Jesus, which would strongly imply she was a perpetual virgin.

Edit: I thought today to add also the Annunciation in Luke (Luke 1:34, in particular). Mary responds to the Angel Gabriel wondering how she could become pregnant, because she is a virgin. At this time, she was already betrothed to Joseph. I think that if my wife had been visited by an angel and told she would conceive a child during our engagement, her assumption would be that that would be a child conceived with me after our wedding. Mary's reaction here is confusing if she is planning to lose her virginity soon to her husband.