Antiphona ad Magnificat (I Vesperis)

From Isaiah 7:14, this antiphon quotes the foundational Marian prophecy: 'Ecce Virgo concipiet et pariet filium, et vocabitur nomen ejus Emmanuel' (Behold a Virgin shall conceive and bear a son, and his name shall be called Emmanuel). The Hebrew 'almah' (young woman) was translated 'parthenos' (virgin) by the Septuagint, confirmed by Matthew 1:23. The name 'Emmanuel' (God with us) establishes Christ's divinity. At First Vespers of the Divine Maternity, this antiphon grounds the feast in prophecy: what Isaiah foretold, Mary fulfilled.