However, it is inferred from one verse only (Luke 1:28), and we have multiple verses in all Gospels and in Acts talking of Jesus' brothers and sisters.
No, it's not inferred from just that one verse. It's inferred from reading that verse and other verses in the context of the Scriptures as a whole, from Genesis all the way through to John's Revelation -- and reading in the way the early Church Fathers did, and the way Christ and the Apostles did, which is typologically. To show you this, I would literally need to take you through just about every book in the Bible, starting with Genesis, to show how the Catholic interpretation of the NT Scriptures of Mary are typologically predicted throughout the OT, and also are fulfilled in the prophecies of John in Revelation, where Mary appears as the Ark of the Covenant. As I have already recommended, a good place to get this sweeping overview, but in a very accessible format, is to read Scott Hahn's book,
Hail, Holy Queen.
My personal experience of being lead to this way of understanding Scripture, and coming to an insight into Mary's role in salvation, has been nothing short of life-transforming. I've always been Christian, but for the first time, when I learned to read the Bible typologically, the Scriptures came alive. It was like discovering a secret code that unlocked mysteries that I would have never even thought to contemplate in the first place, let alone could I have gained insight into them, without it. Granted, it does take a certain leap of faith to enter into the Lord's Word using typological hermeneutics, but this is how the Bible tells us to read it -- so I think you can take the leap from a position of
Sola Scriptura and give it a try without feeling like you are relying on an extra-Biblical authority to do so. But let me explain.
In the letter to the Hebrews, the OT tabernacle and its rituals are described as "types and shadows of heavenly realities" (8:5), and the law as a "shadow of the good things to come" (10:1). St. Peter, in turn, noted that Noah and his family "were saved through water," and that "this prefigured baptism, which saves you now" (1 Pt 3:20-21). Peter's word translated as "prefigured" is actually the Greek word for "typify," or "make a type." The apostle Paul, for his part, described Adam as a "type" of Jesus Christ (Rom 5:14).
So what is a type? A type is a real person, place, thing, or event in the Old Testament that foreshadows something greater in the New Testament. From "type" we get the word "typology," the study of Christ's foreshadowing in the Old Testament (see also,
Catechism, 128-130).
Again, we must emphasize that types are not ficitional symbols. They are literally true historical details. When St. Paul interpreted the story of Abraham's sons as "an allegory" (Gal 4:24), for example, he was not suggesting that the story never really happened; he was affirming it as history, but as history with a place in God's plan, history whose meaning was clear only after its eventual fulfillment.
Typology unveils more than the person of Christ; it also tells us about heaven, the Church, the apostles, the Eucharist, the places of Jesus' birth and death, and the person of Jesus' mother. From the first Christians we learn that the Jerusalem temple foreshadowed the heavenly dwelling of the saints in glory (2 Cor 5:1-2; Rev 21:9-22); that Israel prefigured the Church (Gal; 6:16); that the twelve Old Testament patriarchs prefigured the twelve New Testament apostles (Lk 22:30); and that the ark of the covenant was a type of the Blessed Virgin Mary (rev 11:19; 12:1-6,13-17).
In addition to Old Testament types
explicitly discussed in the New Testament, there are many more that are
implicit but obvious. For example., St. Joseph's role in the early life of Jesus follows the patriarch Joseph's role in the early life of Israel. The two men share the same name; both are described as "righteous," or "just"; both receive revelations in dreams; both find themselves exiled to Egypt; and both arrive on the scene in order to prepare the way for a greater event--in the patriarch Joseph's case, the exodus led by Moses, the Deliverer; in St. Joseph's case, the redemption brought about by Jesus, the Redeemer.
Marian types abound in the Old Testament. We find Mary prefigured in Eve, the mother of all the living; in Sarah, the wife of Abraham, who conceived her child miraculously; in the queen mother of Israel's monarchy, who interceded with the king on behalf of the people of the land; and in many other places, in many other ways (for example, Hannah and Esther). The type addressed most explicitly in the New Testament, the ark of the covenent, is especially well documented and can be demonstrated with overwhelming evidence, both Scriptural and extra-Biblical evidence.
SEE HERE, for example.
But that's the key -- typological reading of the Scriptures as a whole, which unveils the depth and breadth of Catholic Mariology. We're not just relying on a few verses. In addition, we're following tradition, such as St. Jerome's defense of the doctrine of perpetual virginity, as I noted earlier.
A few points in which I disagree with your statement:
Referring to Mary as the NT Ark of the Covenant is a stretch as the AOC was representative of the Mercy Seat of God. It was kept in the Holy of Holies in the temple and was visited only by the Levite high priest once a year for the Day of Atonement sacrifice.
God's special Shekinah glory dwelt on the Mercy Seat atop the Ark of the Covenant. According to the prophet Jeremiah (3:15-17) the Ark of the Covenant will play an important future role.
The Ark of the Covenant was made of acacia wood and covered outside and inside in pure gold. It was 45 inches 27 inches by 27 inches. Three sacred things were placed inside the Ark of the Covenant. Inside were Aaron's sacred rod, which was used to perform miracles in front of Pharaoh; manna, which God gave the Israelites to eat in the wilderness; and, the Ten Commandments on tablets of stone.
To the ancient Hebrews, the Ark was both a divine manifestation and a talisman so powerful that they carried it with them into battle — a weapon of God.
With that history, I fail to see the comparison of the Ark to Mary. It sounds as if you are saying Mary is the new way to come into the presence of God. When Jesus was crucified, the veil that separated the Holy of Holies from the rest of the temple was ripped into two, showing that we can all approach the throne of God and the need for an atoning sacrifice was no longer needed. Jesus was the “Lamb of God who took away the sins of the world” and was the propitiation (satisfactory payment) for our sins and not just expiation (a covering only until the Messiah came).