Who is this gate, if not Mary? Is it not closed because she is a virgin? Mary is the gate through which Christ entered this world, when He was brought forth in the virginal birth and the manner of His birth did not break the seals of virginity.
Some quite emphatically understand this closed gate through which only the Lord God of Israel passes... as the Virgin Mary, who remains a Virgin before and after childbirth. In fact, she remains always a Virgin, in the moment in which the Angel speaks with her and when the Son of God is born.
(Chapter 44, verses 1 onwards) And he brought me back to the way of the outer gate of the sanctuary, which faces eastward and was closed. And the Lord said to me: This gate shall be closed and shall not be opened, and no man shall enter through it, for the Lord God of Israel has entered (or will enter) by it; it shall be closed for the prince. The prince himself shall sit in it to eat bread before the Lord. Through the vestibule (that is, the porch), he shall enter by the gate, and he shall go out by its way. For it is written in Hebrew: 'It shall be shut to the prince.' The Septuagint translated it as: 'It shall be shut, for the leader himself shall sit in it.' There are many gates described in the Scripture of the temple of Ezekiel, both inside and outside. The previous discourse also covers the representation, consecration, and sacrifices of the altar. After this, he comes to the outer gate of the sanctuary, which faces east and is shut. And immediately, the man who was the guide of the prophet and showed him everything spoke to him: This gate that you are looking at will always be shut and will not be opened, and no man will pass through it. And it gives the reason why it is always closed: because the Lord God of Israel has entered, or will enter through it: and it will be closed according to the Hebrew, to the prince, whom the LXX translated as leader. The prince and leader, that is, the Nasi, will sit in it to eat bread before the Lord: and he will enter by way of the vestibule of the gate, and he will go out through it. What is this gate that is always closed, and only the Lord God of Israel enters through it? Namely, the one about which the Savior speaks in the Gospel: Woe to you, scribes and Pharisees, hypocrites! And woe to you, teachers of the law, who take away the key of knowledge! You yourselves do not enter, and you hinder those who are entering (Matthew 23:23). Isaiah also writes about this book under this name: The words of this book shall be like the words of a sealed book: if you give it to a man who cannot read, saying, 'Read this,' he will say, 'I cannot read.' And they shall give the book to a man who knows letters, saying: Read; and he shall say: I cannot read, for it is sealed (Isa. XXIX, 11). But this is the book that no one can unseal or open the seals, neither in heaven, nor on earth, nor under the earth, except for the one of whom it is said in the Apocalypse of John: Behold, the lion of the tribe of Judah, the root and offspring of David, has conquered, so that he may open the book and unseal its seals (Rev. V, 5). For before the Savior assumed a human body and humbled himself, taking on the form of a servant (Phil. II), the Law and the Prophets, and all the knowledge of the Scriptures, were closed, and paradise was closed. But after he hung on the cross, and spoke to the thief, 'Today you will be with me in paradise' (Luke XXIII, 43), immediately the veil of the temple was torn, and everything was opened; and with the veil removed, we say: But we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image, from glory to glory (II Cor. III, 18). But if all things are revealed, for in Christ, according to the words of Paul, all things are revealed (Ibid., XIII), how will the gate be closed and not opened, and a man not pass through it? From these things we learn that even though we have come to the ultimate knowledge, compared to divine knowledge, we now know in part and understand in part; but when that which is perfect comes, then that which is in part will be done away with. Hence, in another place, the Apostle himself speaks of being imperfect and, again, perfect. But if it lacks interpretation, it seems to be the opposite. For he says: Not that I have already obtained, or am already perfect. Brothers, I do not consider myself to have taken hold of it; but one thing I do: forgetting what is behind and straining towards what is ahead, I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus (Philippians 3:12, 14). And when we thought that he, according to his profession, was not yet perfect, and that he was seeking rather than having found what is true, he not only says this about himself, but also about others: Therefore, let us all who are perfect have this same attitude. But the meaning of this place is as follows: Compared to other people who do not have care of the knowledge of the Scriptures or the mysteries of God, I confess that I am perfect; but as for the understanding of the divine majesty, I now see it in an enigma and through a cloud and darkness, and I say with the prophet: Your knowledge is amazing to me, it is confirmed, and I will not be able to attain it (Ps. 138:6). Therefore, this gate, which is closed to everyone (for a man will not pass through it and perish), will be closed to the prince or leader, and it will be opened by his arrival, who will sit in it to eat bread before the Lord, about whom he himself testifies in the Gospel, saying: My food is to do the will of him who sent me, and to accomplish his work (John 4:34). He is the prince and the high priest according to the order of Melchizedek. He is the offering and the priest who, in the presence of the Father, eats heavenly bread with us and drinks wine, of which he speaks in the Gospel: I will not drink of the fruit of this vine until I drink it new with you in my Father's kingdom (Matthew 26:29): in that kingdom, of which he himself and elsewhere says: The kingdom of God is within you (Luke 17:21). And the gate will be closed. No one can truly understand the passion of the Lord, his body and blood as the sacraments of the divine mystery. Such is the greatness of his goodness and the prince of his mercy, that even though he alone sits at the closed door and eats bread before the Lord, he desires to have more companions at his table and feast, and says: Behold, I stand at the door and knock; if anyone opens to me, I will enter in and dine with him, and he with me (Rev. 3:20). But he alone eats bread in the presence of the Lord, because his substance and divine nature are separate from all the substances of creatures. He himself enters and exits through the same gate of the vestibule: for he is both inside and outside, that is, infused and encompassing all; entering through the gate in order to bring with him those who cannot enter without his teaching and help; and exiting in order to bring in others again; and speak to those who do not understand difficult things. But inasmuch as the Eastern gate outside the boundaries of the world is always closed and never opens to human sight, the Gospel of John proves the words of the one who said: No one has ever seen God: the Only Begotten Son, who is in the bosom of the Father, has revealed Him (John 1:18). In other words, it will be closed to everyone except the ruler. The ruler alone will sit in it, to eat the bread of perfect and complete knowledge. For no one knows the Son except the Father, and no one knows the Father except the Son, and those to whom the Son chooses to reveal (Matthew 11:27). Some understand beautifully that the closed gate through which only the Lord God of Israel enters, and the leader to whom the gate is closed, to be the Virgin Mary, who both before childbirth and after childbirth remained a virgin. Indeed, at the time when the angel spoke: The Holy Spirit will come upon you, and the power of the Most High will overshadow you. And behold, you will conceive in your womb and bear a son, and you shall call his name Jesus (Luke 1:35), and when he was born, the virgin remained eternal; to confound those who claim that after the birth of the Savior, she had other sons by Joseph, based on the occasion of his brothers who are mentioned in the Gospel (Mark 3). I know that I wrote a small book in my youth, against Helvidius, the heretic of that time, in Rome.
What means this closed gate in the House of the Lord, except that Mary is to be ever inviolate? What does it mean that 'no man shall pass through it,' save that Joseph shall not know her? And what is this - 'The Lord alone enters in and goeth out by it' - except that the Holy Ghost shall impregnate her, and that the Lord of angels shall be born of her? And what means this—'it shall be shut for evermore' - but that Mary is a virgin before His Birth, a virgin in His Birth, and a virgin after His Birth?
But just as He who was conceived kept her who conceived still virgin, in like manner also He who was born preserved her virginity intact, only passing through her and keeping her closed. [Ezekiel 44:2] The conception, 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.
The ever-virgin One thus remains even after the birth still virgin, having never at any time up till death consorted with a man.
On the contrary, It is written (Ezekiel 44:2): "This gate shall be shut, it shall not be opened, and no man shall pass through it; because the Lord the God of Israel hath entered in by it." Expounding these words, Augustine says in a sermon (De Annunt. Dom. iii): "What means this closed gate in the House of the Lord, except that Mary is to be ever inviolate? What does it mean that 'no man shall pass through it,' save that Joseph shall not know her? And what is this—'The Lord alone enters in and goeth out by it'—except that the Holy Ghost shall impregnate her, and that the Lord of angels shall be born of her? And what means this—'it shall be shut for evermore'—but that Mary is a virgin before His Birth, a virgin in His Birth, and a virgin after His Birth?"
[AD 397] Ambrose of Milan on Ezekiel 44:1-2