The Mass is most itself when it is sung. The Mass itself is a song; it is meant to be sung. At Mass, Christ sings to the Father. In the Gospels, there is only one recorded instance where Jesus is explicitly mentioned as having sung: directly after the Last Supper on the night He was betrayed, when He instituted the Holy Eucharist.
"And when they had sung a hymn, they went out to the Mount of Olives."
— See Mt 26:30 & Mk 14:26
We should not be surprised, that Christ sings when He institutes the Sacrament of Love, and that for the vast majority of the past 2,000 years, the various parts of the Mass have been sung by priests and lay faithful. As a matter of fact, some ancient church traditions say that on Easter Sunday morning, Christ burst out of the tomb singing. We can perhaps add that since then, he has been eagerly waiting for creation to sing back.
"Music stirs our hearts and engages our souls in ways we can't describe. When this happens, we are taken beyond our earthly banishment back to the divine melody Adam knew when he sang with the angels, when he was whole in God, before his exile. In fact, before Adam refused God's fragrant flower of obedience, his voice was the best on earth, because he was made by God's green thumb, who is the Holy Spirit."
— St. Hildegard of Bingen (1098-1179)
The Word became flesh to restore creation's lost symphony. In Sacrosanctum Concilium, the Dogmatic Constitution on the Liturgy, the Second Vatican Council called for a rediscovery of singing during the Mass:
"The musical tradition of the universal Church is a treasure of inestimable value, greater even than that of any other art. The main reason for this pre-eminence is that, as sacred song united to the words, it forms a necessary or integral part of the solemn liturgy." (See No. 112)
Singing the Mass is therefore not about taste or preference. It is about allowing the liturgy to be what it truly is. The liturgy of the Mass is not a gathering with music added on. It is the Church's public act of worship, offered to God by Christ through His Church.
The church calendar, or the liturgical year, is a sacramental, i.e., it is simultaneously a sign of a deeper reality and a means of grace. The deeper reality is the very life of Christ as it is relived by the Church, year after year until the end of time, for Christ is with us as He Himself told us He would be. The Church, the Mystical Body of Christ, is indeed the very Person of Christ living on for each succeeding generation, inviting us to live His life which He presents to us in the liturgy, especially in the Mass.
Year in and year out, the Church leads the entire cosmos through a veritable Theo Drama in which Jesus Christ is the Lord of the Dance. From the moment of his incarnation in his mother's womb, Christ the melodious Word of God that became flesh for us, has never stopped singing and dancing. At the beginning of each liturgical year, He wants us to savour the silent joy of his first coming. During the liturgical seasons of Advent and Christmas, the kind of aura we should sense in the air when we attend a properly celebrated liturgical event is that of the joy of childhood and new beginnings … light and ethereal; like the music of Enya.
During Ordinary Time – the longest period of the liturgical cycle – the piper reminds us of the greatness of the ordinary. Ordinary things like the colour of the grass, the smell of soil and the taste of Ugali and Sukuma Wiki have a charm all of their own. The mood that the liturgy evokes during this longest of seasons (like the 30 years Jesus spend in obscurity) is that even the "apparently boring and monotonous" things of the world are worth celebrating; because God – who is anything but boring – took part in them.
During Lent the music he expects us to resonate with is more solemn and heavy. It is bluesy and bitter-sweet, … of sadness with a hint of hope. It has the gravity and texture of the Negro Spirituals – i.e. of a trapped soul that is yet hopeful because it knows that its release from prison is close at hand. If the step-patterns of the Christmas season resembled the lightness and brightness of a major scale, then the weighty and nostalgic step-patterns of the Lenten period could be expressed best by the minor scales of the solfa ladder. Even the sweet dissonances that often accompany songs sung during this penitential season come off as beautiful because they express so well the redemption that awaits the anguished mood of the longing soul.
As the liturgical year draws to a close, the liturgy reminds us of the glory that awaits those who walk – nay dance – in the footsteps of Jesus Christ; Priest, Prophet and King. The Solemnity of Our Lord Jesus Christ, the King of the Universe, marks the end of the liturgical cycle. It not only wistfully looks back to the glory of Our King's resurrection which we celebrate during the 50 days of Easter, it decidedly points us forward to the final glory that awaits us. The mood of the music proper to such solemnities might remind you of the soundtracks of heroic sagas and legendary films from famous contemporary music composers like Hans Zimmer and John Williams. If moods had colours, the mood for such regal and eschatological liturgical celebrations would be golden. As golden as the setting sun.