The “brothers of Jesus” are mentioned in several passages of the New Testament and even the names of some of them are given: So, in Saint Matthew 12, 46-47, we can read:“While he was speaking to the crowds, his mother and his brethren were standing outside, seeking to speak with him. And someone told him: “Behold, thy mother and thy brethren are standing outside, seeking thee”. In other passages the “brothers” of Jesus are also mentioned: Matthew , 13, 55 and Marcus 6, 3. In Galatians 1, 19 we can read:“But I saw none of the other apostles, except James, the brother of the Lord”.
Nevertheless, we have to bear in mind that, in the Bible, near relatives are called “brothers” (as we see in Genesis 12, 5 in comparison with Genesis 13, 8 and Genesis 14, 14-16): Lot, Abraham’s nephew, is called “his brother”. The same can be said about Jacob and Laban (see Gen 28, 2 and Gen 28, 15).
In other cases, in the Bible, in the Pentateuch, quantities of more than five hundred “brothers” are given, referring to near relatives or descendants of a common stem.
In Chronics I, we can read (Chronics I 26, 30 and 32):“Among the hebronites, Josabia and his brethren, brave men, one thousand and seven hundred…” “it was found that Jeriya’s brothers, brave and hard men, were two thousand and seven hundred, leaders of patriarchal families.”
It is not necessary to say that, as a matter of fact, it is impossible that the one thousand seven hundred brothers can be sons of a same father or mother. Therefore, by saying “brothers” they are referring to the descendants of a common stem or close and distant relatives.
Therefore, the expression “Brethren of Jesus” that we find in the New Testament obviously refers to His close relatives, probably to His first cousins (in some regions of Spain, first cousins are called “cousin-brothers” and, in Catalan, first cousins are “cosins germans” (cousin-brothers) and nowadays, in the Arabian countries, cousins are called “brothers”).
In Galatians 1, 19, we can read:“But I saw none of the other apostles, except James, the brother of the Lord”. So we know that one of the called “brothers” of the Lord was an apostle and was called James. Through other passages, Matthew 10, 2-4, for instance, we know that there were two apostles named James, and in Matthew 4, 21 we find out that one of the two James has Zebedee as a father and through other ways we know that his mother was Salome. (Besides, as we can read in Matthew 20, 20-21 the mother of the two sons of Zebedee says to Jesus:“Say that both my sons sit with you in your kingdom, one to your right and the other one to your left”. If Jesus were their brother, she would not say “my sons”, but “your brothers”!).
Thus, this James cannot be a brother of Jesus. The other James is the son of Alfeus; see, for instance, Matthew 10, 3, ( (Mary, the Blessed Virgin is always called “Jesus' mother”).
On the other hand, we find another Mary who is mentioned as the mother of James and Joseph and, in Marcus, as “the mother of James the Lesser (see Matthew 27, 55-56 and Marcus 15, 40-41; and 47; and16, 1; see also Matthew 10, 2)-3) and, therefore, the name of the mother of James, the son of Alfeus was probably Mary, but she is not the mother of Jesus, because the Blessed Virgin Mary is always called “Jesus' mother”) and in order that James, son of Alfeus, were the brother of Jesus, the Blessed Virgin Mary must have been married in a second wedding to Alfeus, which is not said at all and we are not allowed to suppose it. Therefore, the apostle called “brother of Jesus” is not his brother but his relative. Once it is demonstrated for one of the so-called “brother of Jesus” that he is not a brother but a relative, it is also demonstrated that there is no reason not to believe what our faith tells us: that Mary, the mother of Jesus was a virgin and that she only conceived Jesus by the action of the Holy Spirit.
Furthermore, the Virgin Mary had no more sons, because from the cross she is entrusted to the apostle John, who “from that moment on, he lodged her at his home” (Saint John, 19,27). It would be very strange that, in case she had had other children, she had lived in Saint John’s home.