At Vespers, three lessons from the Old Testament are read. These same Old Testament passages are read at every Feast of the Theotokos.
The story of Jacob's ladder, which is a symbol (or "type") of Mary. In Jacob's dream, a ladder joins heaven and earth. The Church holds that Mary is the fulfillment of this dream, for in her womb she will bear Christ. Truly Mary is the one who joins heaven and earth by giving birth to the Incarnate Son of God!
In Ezekiel's vision, the Lord shows him the east gate of the Temple, through which God enters. After God's entry, the east gate is shut. The Church holds that Mary is the fulfillment of this prophecy. She is the East Gate through whom Christ enters the world, and yet she remains ever Virgin.
Christ is the "wisdom, word, and power of God" as we sing after communion each Sunday, and in this reading we hear that Wisdom has built a house. The Church holds that Mary is the house built by Wisdom, and through whom Wisdom (Christ) is made known to all the world!