From the early Church Fathers to now.
“Because He had spoken all the aforesaid things in the power of His Father’s majesty, therefore the Evangelist proceeds to tell what answer He made to one that told Him that His mother and His brethren waited for Him without; While he yet spake unto the people, his mother and his brethren stood without desiring to see him.”
“And He cannot be held to have thought meanly of His mother, seeing that in His passion He evinced the most extreme carefulness for her.”
“Although they had like the rest power to come in, yet they abstain from all approach to Him, for he came unto his own, and his own received him not. (John 1:11.)”
“(in Luc. 8:21.) Nor does He overthrow the duty of filial submission, which is conveyed in the command, Honour thy father and thy mother, (Ex. 20:12.) but shews that He owes more to the mysteries and relationship of His Father, than of His mother; as it follows, And stretching out his hand to his disciples, he said, Behold my mother and my brethren.”
“(Hom. xliv.) But mart the loftiness of His brethrena; when they should have come in and heartened with the crowd, or if they would not this, to have waited the end of His speech, and then to have approached Him—they on the contrary call Him out to them, and do this before the multitude, therein shewing their superabundant love of honour, and also, that with all authority they lay their commands upon Christ. This the Evangelist covertly hints when he says, While he yet spake; as much as to say, Was there no other time? But what did they seek to say? Was it aught of the dogmas of truth? then should they have brought it forth before all, that all might profit thereby. But if of other things that concerned themselves alone, they should not have called Him in such haste, whence it is plain that they did this out of vain glory.”
“For He said not, Go and say unto her, She is not My mother, but continues His discourse to him that had brought Him word; as it follows; But he answered and said unto him that told him, Who is my mother? and who are my brethren?”
“But had He desired to disown His mother, He would have done it at the time when the Jews cast His birth in His teeth.”
“And besides what has been said, He taught also somewhat more, namely, that we should not neglect virtue relying on any kindred. For if it profited His mother nothing that she was such, if she had not had virtue, who is there that shall be saved by his kindred? For there is one only nobility, to do the will of God, and therefore it follows, Whoso shall do the will of my Father which is in heaven, the same is my brother, and sister, and mother. Many women have blessed that holy Virgin and her womb, and have desired to be made such mothers. What is it then that hinders? Behold, He hath set before you a broad way, and not women only, but men likewise, may become the mother of God.”
“(cont. Helvid. 14, et seq.) From this is taken one of Helvidius’s propositions, on the ground that mention is made in the Gospel of the brethren of the Lord. How, says he, are they called brethren of the Lord, if they were not his brethren? But now it should be known that in divine Scripture men are said to be brethren in four different ways, by nature, by nation, by kindred, and by affection. By nature, as Esau and Jacob. By nation, as all Jews are called brethren, as in Deuteronomy, Thou shalt not set over thee a foreigner who is not thy brother. (Deut. 17:15) They are called brethren by kindred who are of one family, as in Genesis, Abraham said unto Lot, Let there not be strife between thee and me, for we are brethren. (Gen. 13:8) Also men are called brethren by affection, which is of two kinds, special and general. Special, as all Christians are called brethren, as the Saviour says, Go tell my brethren. General, inasmuch as all men are born of one father, we are bound together by a tie of consanguinity, as in that, Say unto them that hate you, Ye are our brethren. (Is. 66:5 sec. LXX.) I ask then, after which manner these are called the Lord’s brethren in the Gospel? According to nature? But Scripture saith not, neither calling them sons of Mary nor of Joseph. By nation? But it is absurd that some few out of all the Jews should be called brethren, seeing that all the Jews who were there might have thus been called brethren. By affection, either of a human sort, or of the Spirit? If that be true, yet how were they more His brethren than the Apostles, whom He instructed in the inmost mysteries. Or if because they were men, and all men are brethren, it was foolish to say of them in particular, Behold, thy brethren seek thee. It only remains then that they should be His brethren by kindred, not by affection, not by privilege of nation, not by nature.”
“(in loc.) But some suspect the brethren of the Lord to be sons of Joseph by another wife, following the idle fancies of apocryphal writers, who have coined a certain woman called E sea. But we understand by the brethren of the Lord, not the sons of Joseph, but cousins of the Saviour, sons of a sister of Mary, an aunt of Our Lord, who is said to be the mother of James the Less, and Joseph, and Jude, whom in another place of the Gospel we find called the brethren of the Lord. (Mark 6:3) And that cousins are called brethren, appears from every part of Scripture.”
“He that delivers this message, seems to me not to do it casually and without meaning, but as setting a snare for Him, whether He would prefer flesh and blood to the spiritual work; and thus the Lord refused to go out, not because He disowned His mother and His brethren, but that He might confound him that had laid this snare for Him.”
“He did not then, as Marcion and Manichæus say, disown His mother, so as to be thought to be born of a phantasm, but He preferred His Apostles to His kindred, that we also in a comparison of our affections should set the spirit before the flesh.”
“Let us also expound in another way. The Saviour is speaking to the multitude—that is, He teaches the Gentiles the inward mysteries; His mother and His brethren, that is the synagogue and the Jewish people, stand without.”
“And when they shall have asked and enquired, and sent a messenger, they shall receive for answer, that their will is free, and that they can enter in, if they will believe.”
“(De Cons. Ev. ii. 40.) We are to understand without doubt that this happened close upon the foregoing; for he begins to tell it with the words, And while he yet spake. What can that yet mean but that it was at the very time He spake the foregoing things? Mark also follows up that which He had said concerning blasphemy against the Holy Ghost, by saying, And there came his mother and his brethren. (Mark 3:31) Luke has not observed the order of action here, but has placed this earlier as he happened to recollect it.”
“(De Nat. et Grat. 36.) But whatever may be decided concerning these brethren, yet concerning the holy Virgin Mary, (for the honour of Christ,) when sin in her is in question, I would not have it brought into doubt. For from this only we might know that more abundant grace was conferred upon her that she should overcome sin on all sides, because she merited to conceive and bring forth Him Who it is clear had no sin. It follows; Then said one unto him, Behold, thy mother and thy brethren stand without seeking thee.”
“(Hom. in Ev. iii. 2.) The Lord deigned to call faithful disciples His brethren, saying, Go, tell my brethren. Since then a man may be made a brother of the Lord by coming to the faith, it should be enquired how one may become also His mother. Be it known by us then, that he that by believing is made brother or sister of Christ, becomes His mother by preaching; for in pouring Him into the heart of the hearer, he may be said to beget the Lord; and he is made the Lord’s mother, when by his word love of the Lord is begotten in the mind of his neighbour.”
“(ubi sup.) Thus also His mother is declared to stand without, as though she was not acknowledged, because the synagogue is therefore not acknowledged by its Author, because it held to the observance of the Law, and having lost the spiritual discernment thereof, kept itself without to guard the letter.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.