During the Vespers of Advent to enrich our spirituality in preparation for Christmas, from December 17 to the 23, the Major Antiphons of the Magnificat are exclaimed sublimely and powerfully in Gregorian chant. The “O Antiphons” texts, as they are also known, were introduced into the Roman liturgy in the eighth century, originating from the Psalms and the Holy Scriptures. Each day a Messianic title from the Old Testament beginning with the word “O” is exclaimed in Latin. Apart from chanting the exclamation in the Liturgy of the Hours, the text of these antiphons has become popular in the vernacular language and is sung at other times in the Holy Mass: during the Introit, communion, and offertory. The most popular hymn of the “O Antiphons”, translated into several languages, is “O come, O come, Emmanuel”. In addition, we have mentioned in previous articles that in the area of popular piety they are prayed with much devotion during the Christmas novena. It is worth noting that the initials of these antiphons written backward spell the word ERO CRAS (Emmanuel, Rex gentium, Oriens, Clavis David, Radix Iesse, Adonai, Sapientia), which is an acrostic that means “Tomorrow, I will come”. The “O” antiphons are not to be confused with the Marian antiphons. The liturgy of the Church has concentrated on preparing us for the coming of the Lord, so that we may welcome Christ into our hearts with good will. Let us adore the Sovereign King who will come to save us, accompanied by the nuns of Jouques, singing with love and joy the “O Antiphons”.