Mt 1:24f  ‘He took his wife, but did not have marital relations with her until she gave birth to a son, whom he named Jesus.’

Mt 12:46–50 — While Jesus was still speaking to the crowds, his mother and brothers came and stood outside, asking to speak to him. 47 Someone told him, “Look, your mother and your brothers are standing outside wanting to speak to you.” 48 To the one who had said this, Jesus replied, “Who is my mother and who are my brothers?” 49 And pointing toward his disciples he said, “Here are my mother and my brothers! 50 For whoever does the will of my Father in heaven is my brother and sister and mother.”

Mt 13:55f  ‘Isn’t this the carpenter’s son? Isn’t his mother named Mary? And aren’t his brothers James, Joseph, Simon, and Judas? And aren’t all his sisters here with us?’

Mk 6:3 ‘”Isn’t this the carpenter, the son of Mary and brother of James, Joses, Judas, and Simon? And aren’t his sisters here with us?” And so they took offense at him.’

Jn 2:12 ‘After this he went down to Capernaum with his mother and brothers and his disciples, and they stayed there a few days.’

See also Gal 1:9; 1 Cor 9:5.

Summary.  The ‘brothers and sisters’ referred to in the above texts are variously thought to have been siblings of Jesus with the same biological mother and father (this would discount the virginal conception of Jesus), cousins of Jesus, children of Joseph by a previous marriage, or younger siblings of Jesus.  The last of these is the most probable.

Morris (cited by Bruner) summarises the three answers given by the early church:-

1. the Helvidian answer (after the fourth-century theologian Helvidius), that Mary was not perpetually a virgin and that Jesus’ brothers were the later natural children of Joseph and Mary (citing Matt. 1:25 and Luke 2:7 in evidence; Matt. 1:25 reads, “but [Joseph] had no marital relations with her until [heōs] she had borne a son,” NRSV); Luke 2:7: “And she gave birth to her firstborn son,” NRSV).
2. the Epiphanian answer (after Epiphanius, another fourth-century theologian), that the brothers were children of Joseph by a former marriage;
3. the Jeromian answer (after Jerome, a late-fourth- early-fifth-century Father) that the children were Jesus’ cousins.  This view is widely-held in the Roman Catholic Church.

Mary – a perpetual virgin?

Traditional Roman Catholic teaching denies that Mary had any children other than Jesus.  This has been its official teaching (and that of the Greek Orthodox church) since the Council of Chalcedon in AD 451.  However, the belief was widely held in the early church, and proponents included Jerome, Gregory of Nyssa and others.

Dating from the 2nd century, the Proevangelium of James repeatedly mentions the perpetual virginity of Mary, the assumption being that Jesus’ brothers are sons of Joseph from a previous marriage.

Referring to the Proevangelium of James, Brittany E. Wilson (Women’s Bible Commentary, art. ‘Mary and her Interpreters’) comments:

‘In this noncanonical Christian text, Mary is both the main character and the paragon of sacred purity. Not only is she miraculously conceived to the delight of her parents Anna and Joachim, but Mary remains a virgin before, during, and after Jesus’ birth. This emphasis on Mary’s chastity and perpetual virginity is probably due in part to Jewish polemic that identified Mary as a harlot who conceived Jesus out of wedlock. Regardless of its apologetic function, however, this influential second-century text had a huge impact on understandings of Mary that can still be felt to this day.’

According to Ott, Fundamentals of Catholic Dogma, Catholics believe that

‘Mary was a Virgin before, during and after the Birth of Jesus Christ…Mary bore her son without any violation of her virginal integrity…Mary gave birth in miraculous fashion without opening of the womb and injury to the hymen, and consequently also without pains.’ (Quoted in Geilser and MacKenzie, Roman Catholics and Evangelicals, p300).

Bede:

‘We, dearly beloved brothers, without any hesitation or questioning must be aware and confess that not only the blessed Mother of God, but also Joseph, the most blessed witness and guardian of her chastity, always remained wholly aloof from the conjugal act; and further, that those who after the customary manner of the Scriptures are called our Savior’s brothers or sisters were not their children but their relatives.’ (ACCS)

Concerning the notion that Mary remained a virgin during the birth of Jesus, Geisler and MacKenzie respond:

‘First, the fact that Mary “brought forth” Jesus at his birth does not indicate that it was miraculous. Rather, this is the normal way to indicate that, in the absence of a birthmaid, she delivered her own child.

‘Second, all the descriptions of Christ’s birth indicate a normal birth, such as “born of a woman” (Gal. 4:4); “brought forth” (Luke 2:7); “delivered” (Luke 2:6); “birth” (Matt. 1:18); “born” (Matt. 2:2).

Third, the Bible does not use any of the normal words for a miracle (sign, wonder, power) when speaking of Jesus’ birth, only of his conception (cf. Isa. 7:14 and Matt. 1:18–23).

‘Fourth, it diminishes the humanness of the incarnational event to posit a miracle at the point of Jesus’ birth rather than his conception, as the Bible does. As the God-man, Jesus was human in every way possible apart from sin (Heb. 4:15).

‘Fifth, the idea of a miraculous birth of Christ, without coming through the birth canal or causing pain, is more Gnostic than Christian. It is more like an event found in a second- or third-century apocryphal book than a first-century inspired Book.’

(Paragraphing added)

Many Protestants, too, have clung to this doctrine of the perpetual virginity of Mary.  These include Luther, Calvin and Zwingli.

Luther:

‘She was a virgin before the birth of Christ (ante partum) and remained one at the birth (in partu) and after the birth (post partum),” even going so far as to affirm that “it neither adds nor detracts from faith. It is immaterial whether these men were Christ’s cousins or his [half-] brothers p 302 begotten by Joseph.’ (Quoted by Geisler and MacKenzie)

Calvin (on Mt 13:55) –

‘It was, we are aware, by the wonderful purpose of God, that Christ remained in private life till he was thirty years of age. Most improperly and unjustly, therefore, were the inhabitants of Nazareth offended on this account; for they ought rather to have received him with reverence, as one who had suddenly come down from heaven. They see God working in Christ, and intentionally turn away their eyes from this sight, to behold Joseph, and Mary, and all his relatives; thus interposing a veil to shut out the clearest light. The word brothers, we have formerly mentioned, is employed, agreeably to the Hebrew idiom, to denote any relatives whatever; and, accordingly, Helvidius displayed excessive ignorance in concluding that Mary must have had many sons, because Christ’s brothers are sometimes mentioned.’

and on 1 Cor 9:5 –

‘In the first place, he brings forward the Apostles He then adds, “Nay, even the brethren of the Lord themselves also make use of it without hesitation — nay more, Peter himself, to whom the first place is assigned by consent of all, allows himself the same liberty.” By the brethren of the Lord, he means John and James, who were accounted pillars, as he states elsewhere. (Galatians 2:9.) And, agreeably to what is customary in Scripture, he gives the name of brethren to those who were connected with Him by relationship.’

and on Gal 1:19 –

‘Who this James was, deserves inquiry. Almost all the ancients are agreed that he was one of the disciples, whose surname was “Oblias” and “The Just,” and that he presided over the church at Jerusalem. Yet others think that he was the son of Joseph by another wife, and others (which is more probable) that he was the cousin of Christ by the mother’s side: but as he is here mentioned among the apostles, I do not hold that opinion. Nor is there any force in the defense offered by Jerome, that the word Apostle is sometimes applied to others besides the twelve; for the subject under consideration is the highest rank of apostleship, and we shall presently see that he was considered one of the chief pillars (Galatians 2:9). It appears to me, therefore, far more probable, that the person of whom he is speaking is the son of Alpheus.’

Commenting on Mt 1:25, Calvin cautions against speculation –

‘This passage afforded the pretext for great disturbances, which were introduced into the Church, at a former period, by Helvidius. The inference he drew from it was, that Mary remained a virgin no longer than till her first birth, and that afterwards she had other children by her husband. Jerome, on the other hand, earnestly and copiously defended Mary’s perpetual virginity. Let us rest satisfied with this, that no just and well-grounded inference can be drawn from these words of the Evangelist, as to what took place after the birth of Christ. He is called first-born; but it is for the sole purpose of informing us that he was born of a virgin. It is said that Joseph knew her not till she had brought forth her first-born son: but this is limited to that very time. What took place afterwards, the historian does not inform us. Such is well known to have been the practice of the inspired writers. Certainly, no man will ever raise a question on this subject, except from curiosity; and no man will obstinately keep up the argument, except from an extreme fondness for disputation.’

(See here for the source of these quotes from Calvin)

The Geneva Bible notes allow for (but do not insist upon) the possibility that ‘cousins’ or other ‘near kinsmen’ are meant.  Matthew Poole adopts the same view.

The Jamieson, Fausset and Brown commentary, on Mt 13:55, surveys the options without coming to a definite interpretative decision:

‘An exceedingly difficult question here arises—What were these “brethren” and “sisters” to Jesus? Were they, First, His full brothers and sisters? or, Secondly, Were they his step-brothers and step-sisters, children of Joseph by a former marriage? or, Thirdly, Were they His cousins, according to a common way of speaking among the Jews respecting persons of collateral descent? On this subject an immense deal has been written; nor are opinions yet by any means agreed. For the second opinion there is no ground but a vague tradition, arising probably from the wish for some such explanation. The first opinion undoubtedly suits the text best in all the places where the parties are certainly referred to (ch. 12:46, and its parallels, Mark 3:31, and Luke 8:19; our present passage, and its parallel, Mark 6:3; John 2:12; 7:3, 5, 10; Acts 1:14). But, in addition to other objections, many of the best interpreters, thinking it in the last degree improbable that our Lord, when hanging on the cross, would have committed His mother to John if He had had full brothers of His own then alive, prefer the third opinion; although, on the other hand, it is not to be doubted that our Lord might have good reasons for entrusting the guardianship of His doubly widowed mother to the beloved disciple in preference even to full brothers of His own. Thus dubiously we prefer to leave this vexed question, encompassed as it is with difficulties.’

Perhaps surprisingly, Ryle – a staunch Protestant – thinks that

‘there is no good ground for supposing that these were our Lord’s brethren according to the flesh, and that Mary ever had any other son after our Lord’s miraculous birth.—For one thing, it is well known to every careful reader, that the word “brethren” is applied in the Bible to many relatives besides those whom we call “brethren.” Abraham says to Lot, “We be brethren,” (Gen 13:8,) though Lot was his nephew. Mishael and Elzaphan were called the “brethren” of Nadab and Abihu, though they were only cousins. (Lev 10:4.)—Jacob said “to his brethren” gather stones (Gen 31:46); yet they were his sons and servants.—For another thing, it is quite possible that Joseph might have had children by a former marriage, before he was espoused to Mary; and these children, we can well understand, would be called our Lord’s “brethren.”—In the last place, we know that the Apostle James was called our “Lord’s brother,” (Gal 1:19,) and yet we are distinctly told that he was the son of Alpheus or Cleophas, the husband of the virgin Mary’s sister. It is therefore most probable that “brethren” in the verse before us means “cousins,” some of whom believed on our Lord, though others did not. (Jn 7:5.)’

I think that this esteemed writer has shown that his opinion is ‘possible’, but not that it is ‘probable’.  Ryle appears to be following a traditional, and unscripturally prudish approach.

Some (to quote Ott again)

‘note that the fact that the dying Redeemer entrusted His Mother to the protection of the Disciple John (John 19:26), “woman, behold thy Son,” presupposes that Mary had no other children but Jesus.’

But, as Geisler and MacKenzie point out:

‘The fact that Jesus commended his mother to John at the cross need not imply that he had no brothers but only that they were not present, so he could not turn the responsibility over to them. Besides this, Jesus’ brothers were not at this time believers (cf. John 7:5), so it was important that Mary be left in good spiritual hands.’

Apparently,

‘Pope Siricius (A.D. 384–399)…argued that it would be horrifying to think of another birth issuing from the same virginal womb from which the Son of God was born.’

One suspects that it is this (misplaced) horror, rather than biblical evidence or sanctified reasoning, which is the main driver in the dogma of Mary’s perpetual virginity.  Referring to a work by Elliot Miller and Kenneth Samples, Geisler and MacKenzie remark:

‘Since there is nothing defiling about sexual relations within marriage (Heb. 13:4), to suggest that Christ would not want to be conceived in a womb that would later conceive other humans is to take away from the glory that God would afterward give him for his voluntary humility in becoming human (Phil. 2:9–11).’

The Helvidian view

Helvidius was a critic of the ‘cousins’ theory of Jerome.  According to Pate (40 Questions About The Historical Jesus), he argued that

1. Matthew 1:18, 25 imply that Joseph did “know” Mary (that is, have sexual relations with her) after the birth of Jesus because it says he did not know her until then. The reference to Mary being found with child “prior to when they came together” refers to prior to when they had sexual relationship, not merely prior to when they lived in the same house.
2. The reference to Jesus as Mary’s firstborn son (Luke 2:7) implies she had others later.
3. Various passages mention Jesus’ brothers and sisters.
4. Tertullian agreed with this view, as did Victorinus of Pettau.
5. It was no dishonor that Mary was a real wife to Joseph, as the patriarchs all had wives.

The Epiphanian view, held by the Orthodox today, is that Jesus’ siblings were children of Joseph from a previous marriage.

So the Orthodox Study Bible:

‘In Jewish usage, brother can indicate any number of relations. Abram called his nephew Lot “brother” (Gn 14:14); Boaz spoke of his cousin Elimelech as his “brother” (Ruth 4:3); and Joab called his cousin Amasa “brother” (2Kg 20:9). Christ Himself had no blood brothers, for Mary had but one Son: Jesus. The brothers mentioned here were either stepbrothers, sons of Joseph by a previous marriage, or cousins. Indeed, Jesus commits His mother to the care of John at the Cross (Jn 19:25–27), which would have been unthinkable if Mary had had other children to care for her.’

Regarding the last-mentioned point, it is by no means ‘unthinkable’ that Jesus committed Mary to the care of John if she had other children to care for her: for, firstly, Jesus’ brothers were all unbelievers at that time; and, secondly, we know that Jesus had a particularly intimate relationship with John (closer, no doubt, than many relationships between blood brothers).

Witherington (cited by Pate) advances the following arguments against this position:

1. There is no mention of the brothers of Jesus in the infancy narratives or in Luke 2:41–52.
2. Matthew 1:25 does not prohibit Mary and Joseph from having a sexual relationship after the birth of Jesus.
3. The absence of Joseph from accounts of Jesus’ ministry does not mean he had to be older or that he was previously married.
4. The fact that the brothers of Jesus are often associated with Mary in all four gospels suggests she is their mother.
5. Most important, there is nothing arising in the gospel texts to push us in this interpretive direction. This scenario has to be brought from outside and imposed on the biblical texts.

The texts that refer to Jesus’ family almost always imply that his brothers and sisters were actual brothers and sisters, and not cousins.  For example:

Mt 13:55  ‘Isn’t this the carpenter’s son? Isn’t his mother named Mary? And aren’t his brothers James, Joseph, Simon, and Judas?’

Geisler and MacKenzie comment:

‘For one thing, “brothers” and “sisters” are mentioned in the context of the family with the “carpenter’s son” and “mother,” which clearly indicates they are immediate blood brothers. For another, the Greek term for “brother” (adelphos) here is the normal word for “blood brother.” In fact, there is no a single example where adelphos is used for “cousin” in the New Testament. There is a word for “cousin” (anepsios), as in Colossians 4:10, where Mark is described as “the cousin [anepsios] of Barnabas.” But this word is not used in Matthew 13 or in any passage referring to Jesus’ brothers and sisters. Finally, the words “brother” and “sister” are used many other times in the New Testament in a family connection, always meaning a literal blood brother or sister (Mark 1:16, 19; 13:12; John 11:1–2; Acts 23:16; Rom. 16:15).’

If, as some speculate, the ‘brothers and sisters’ were from a previous marriage of Joseph, then,

‘Joseph’s oldest son would have been heir to David’s throne and not Jesus, but the Bible affirms that Jesus was the heir (Matt. 1:1).’

The contributor to ISBE (1st ed., art. ‘Mary’) suggests two further lines of thought:

1. Even if it could be shown that Mary had no other children than Jesus, this does not prove her virginity (perpetual or otherwise).

2. ‘If Mary was married to Joseph and Joseph to Mary in appearance only, then they were recreant to each other and to the ordinance of God which made them one. How a Roman Catholic, to whom marriage is a sacrament, can entertain such a notion is an unfathomable mystery. The fact that Mary was miraculously the mother of the Messiah has nothing to do with the question of her privilege and obligation in the holiest of human relationships. Back of this unwholesome dogma are two utterly false ideas: that the marriage relationship is incompatible with holy living, and that Mary is not to be considered a human being under the ordinary obligations of human life.’

On the meaning of the word ‘adelphos‘, Murray Harris (Navigating Tough Texts) comments that

‘In the OT, it can on occasion refer to male “relatives” of various degrees of genealogical closeness (e.g., Gen 13:8; 29:12).’

But in the NT, the main uses are

1. A member of the Christian community, a “brother” in Christ (e.g., Rom 16:23; 1 Cor 1:1).
2. Those with a close spiritual affinity with Jesus (e.g., Matt 12:49–50; 25:40; Mark 3:33–35; Luke 8:21; Heb 2:11–12), especially his disciples (e.g., Matt 28:10; John 20:17).
3. Males from the same womb of a particular woman (Matt 12:46–47; 13:55; Mark 3:31–32; 6:3; Luke 8:19–20; John 2:12; 7:3, 5, 10; Acts 1:14; 1 Cor 9:5; Gal 1:19).

Other Greek words were available to indicate different family relationships:

‘If the brothers of Jesus were simply his male relatives, there was a Greek word to convey this—syngenēs, meaning “relative,” “someone belonging to the same family,” “kinsman” (used in Mark 6:4). If the brothers were simply cousins, again a special word was available—anepsios, “cousin” (used in Col 4:10 in reference to Mark, the cousin of Barnabas).’