They were apparently, though there are many disagreements, the children of Mary of Cleopas, the Theotokos's own sister. Compare Mk 2 and Jn 19:25. Jude the brother of James is the same as Levi the son of Alphaeus, Mt 10:3, as Bishop Michael indicates with references at this passage.
Yet we must say that, by comparing Mk 2 with Lk 5:27, 29 and Mt 9:9, where the calling of the publican, or tax collector, is recounted, the Apostle and Evangelist Matthew, "Matthew the publican" in Mt 10:3, is identified with Levi the son of Alphaeus. In general, this question is very difficult.
Second, in all probability the Lord's brothers who did not believe in Him were the sons of Joseph the Betrothed from his first marriage. Blessed Theophylact indicates this beautifully when commenting on this passage of John.
We must add that St. John Chrysostom, in Homily 48 on John, thinks that those who reproached Him included the Apostles Jude and James. He does this by identifying them with the persons named in Mt 13:55. But compare Mk 3 and 34. It is hard to suppose that the Apostles were among those who said, "He is beside Himself."
Blessed Theophylact says: "His brothers reproach Him, plainly the children of Joseph, as being assailed by two passions, fear and love of glory." He continues: "Whence came such unbelief in them? From a corrupt will and envy. For relatives are always accustomed to envy their own more than strangers."
In citing these words of blessed Theophylact, we point out that we cannot allow that any of the Apostles, apart from Judas Iscariot, were among the unbelieving brothers.
Theophylact, following John Chrysostom, does indeed seem inclined to think that Jude the brother of James and James the son of Alphaeus were among them. Yet, apart from what has already been said, we must consider the bitter words of reproach, which are impossible in the mouths of the Apostles.
We should also note that the Lord says to them below, in verse 8: "You go up to this feast." According to verse 10, they did indeed go. But could the Apostles have gone up to the feast apart from the Lord?
All this comes down to the fact that we do not recognize Jude the brother of James and his brother James the son of Alphaeus as sons of Joseph the Betrothed. James later became bishop of the Church of Jerusalem, Acts 12:17; 15:13; Gal 2:9. We see them only as persons legally related to the Lord's brothers according to the flesh.
As for the sons of Joseph from his first marriage, listed in Mt 13:55, we think of the Lord's word: "A prophet is not without honor except in his own country and in his own house." These words are spoken after the listing of the Lord's brothers, James, Joses, Simon, and Jude, in Mt 13:57.
There seems to be no doubt that these are precisely the relatives who, in Mk 3, "went out to seize Him, for they said, 'He is beside Himself.'" We also think that they not only did not believe in the Lord, but, as blessed Theophylact proves, they also envied Him.
These brothers of the Lord were probably sons of the aged Joseph from a very early marriage. They were far older in years than the Lord Jesus and apparently allowed themselves to give Him advice. Such is the advice in the present passage of the Gospel we are reading.
In it, besides unbelief, one also hears a hidden desire to make use of this world's goods, if, as they thought, the Lord Jesus became king. "Show Yourself to the world," they say. They probably allude also to the fact that the Lord, as we said above, had not been in Jerusalem at the second Passover, but had spent it in Galilee.
Perhaps the Lord's unbelieving brothers expected that in Jerusalem, as had happened in Galilee, the crowd of people would wish to make Him king by force. They may have thought that He would be unable to decline this title, which would bring them reputation and wealth.