"Behold, a virgin shall conceive and bear a son, and shall call his name Imman'u-el." This text is one of the clearest Messianic prophecies of the Old Testament. "Ecce"; "Behold": This word is repeated often throughout the piece to signal something mysterious, miraculous, to grab the listener's attention. We might say in English sometimes: "Give ear", pay attention.
"Virgo"; This word fixes in the mind a young, unwed woman. But what about her? "Concipiet"; "She will conceive"- In this word lies the mystery! A virgin will conceive, be with child! Only God could do such a thing. At this word His awesome power is shown forth. Hence, it stands alone after the repetitions of "Ecce, virgo". "Et pariet… filium." The sheer mystery is prolonged with the word "Pariet", with the constant presence of the augmented fourth interval. "She will bear, the virgin will bring forth". But with the sudden shift to a major mode at "filium", the incomprehensible mystery becomes concrete and particular- the very real, profound joy of a mother and her newborn child. "She will bear a son".
But we know who the virgin-mother is, and who the son is. And so the piece ends with "Et nomen Virginis: Maria", from the Infancy narrative in Luke's Gospel. The sweet, holy name of Mary is proclaimed again and again because it is a name that speaks saving peace and consolation to the soul, the saving peace and consolation of Her Son, Jesus Christ, whose first coming we are preparing to celebrate, and whose second coming we ought to prepare for every day of our lives.