Gaudens Gaudebo—I Will Greatly Rejoice relies on three themes, two Georgian chants, played off of a third theme. All three are introduced within the first 4 measures. With rising and rhythmic improvisational manner, the Gregorian Chant, Gaudens Gaudebo is most prominent from the very beginning.
Then, suggested in places is the familiar Mode I, Plainchant, Ave Maria.
Most conceptual of all, and often the accompaniment for the first two themes, is a third theme—the “Yes!” theme of Mary’s joy in doing God’s will. Merely hinted at in measures 3-4, it first appears in its fullness at measure 18:
Mary’s reply to God in the “Yes!” theme, a period of struggle and doubt arrives, followed by prayer. In any life-altering decision, one may be plagued with questions, fear of the unknown, and doubt. No matter how certain, one must confront these emotions, followed by prayer: Measures 43-53 enter into an improvisational variation upon Gaudens gaudebo. It is mixed with great uncertainty, a nervous playfulness of youth, doubt, but still struggling forward. This section is immediately followed by an en prière variation of Gaudens gaudebo (m. 54-65). It is a time of deep meditation, a prayer to find clarity, certainty, and the strength to carry out God’s will.
From this point forward, the Gaudens gaudebo theme is presented with great rhythmic energy, as Mary carries out what she consented to do. (m. 66-94)
At measure 97, an arpeggiated “Yes!” theme returns in the manuals, with variations of Gaudens gaudebo in the pedal. This chorale section travels through various keys, finally giving way to the toccata (m. 132). This toccata, with a rhythmic “Yes!” drives the Ave Maria plainchant in the pedal.
Working towards culmination, the manuals slowly rise and fall in chromatic harmonies. It is at this time a fourth theme appears only once (m. 144-156): the Easter Compline hymn Regina Caeli is quoted in its entirety summarizing Mary’s necessary role in salvation history: “For He whom you have humbly borne for us, Alleluia! Has arisen as He promised! Alleluia!” One sings of motherhood and resurrection in the same verse.
Finally, all three major themes are declared with great youthful exuberance, and joy!
“Without God’s Son, nothing could exist; without Mary’s Son, nothing could be redeemed.” –St. Anselm