Mary, Ark of the New Covenant
The question
Calling Mary the Ark of the Covenant sounds like a stretch — is it really in the Bible?
Scripture · Luke 1:43
And why is this granted me, that the mother of my Lord should come to me?
A short answer
It does sound like a reach at first — comparing a woman to a gold-covered box. But Luke clearly wrote his account of the Visitation to make you think of the Ark, and the parallels are too tight to be coincidence. In 2 Samuel 6, David brings the Ark up into the hill country of Judah; in Luke 1, Mary travels into the hill country of Judah. David asks, "How can the ark of the Lord come to me?" Elizabeth asks, "Why is this granted me, that the mother of my Lord should come to me?" (Luke 1:43; 2 Samuel 6:9).
It keeps going. David "leaped and danced before the Lord"; the baby John "leaped" in Elizabeth's womb (2 Samuel 6:16; Luke 1:41). The Ark stayed in the hill country three months; Mary stayed with Elizabeth "about three months" (2 Samuel 6:11; Luke 1:56). Luke is practically waving a flag.
The point is what the Ark held: the word of God on stone, manna, and Aaron's priestly staff. Mary carried the Word made flesh, the true Bread from heaven, our great High Priest — the realities those things only foreshadowed. The Catechism notes she's the dwelling place where God came to live among us (CCC 2676). The old Ark was holy because of what it touched; how much more the living woman who carried God Himself.