In Isaiah 7:14, the Prophet announces that a Virgin shall conceive and bear the son who will be Immanuel – “God with us.”
Isaiah further prophesied:
“In that day the deaf shall hear the words of a book, and out of their gloom and darkness the eyes of the blind shall see. The meek shall obtain fresh joy in the LORD, and the poor among men shall exult in the Holy One of Israel” (Isaiah 29:18-19).
Isaiah’s prophecy inspired the author of the Canon for the Sunday of the Paralytic to write these words:
In days of old Isaiah beheld you, ever-Virgin,
as the book in which the timeless Word
was written by the finger of the Father!
He saves us from all senseless lack of reason,
as we sing songs of praise to you with holy words!
(From the 8th Ode of the Canon)
St. John the Theologian in his Gospel is clear that Jesus is the Word of God.
In the beginning was the Word, and the Word was with God, and the Word was God. … And the Word became flesh and dwelt among us, full of grace and truth; we have beheld his glory, glory as of the only Son from the Father. (John 1:1)
Indeed, Mary as Theotokos can be poetically perceived as the book in whom the Word of God was written as the Canon Hymn has the Holy Prophet Isaiah saying.
For if Christ is the Word of God, then indeed Mary is the one who gives flesh to that word and makes the Word visible to us.