In the Roman Rite of the Mass, on Sundays and solemnities, the Liturgy of the Word is typically composed of the First Reading, Psalm, Second Reading, and Gospel.
However, that changes on a small number of special days, where the Church has retained what are called "sequences," many of which were developed during the Middle Ages. They occur after the Second Reading and before the Gospel, which can be a little jarring to the average churchgoer who is accustomed to the normal rhythm of Mass. This "jarring" is a good thing, as it reminds us how special the day is!
The purpose of these liturgical sequences is to offer a poetic summary of the spiritual theme of the Mass.
In the case of the feast of Corpus Christi, St. Thomas Aquinas was asked by Pope Urban IV to compose a special sequence that highlighted the institution of the Eucharist and Jesus' Real Presence.
Lauda Sion
St. Thomas Aquinas wrote the sequence for Corpus Christi around the year 1264, and it is one of the few sequences that the Roman Rite has retained.
It's a beautiful sequence, one that was born out of Aquinas' rich spiritual and intellectual life. It shows how Aquinas could not only write a complex theological treatise, but also an artistic poem.
If you have never read or reflected on this sequence, spend some time today reading this poem that is over 750 years old.
Laud, O Zion, your salvation,
Laud with hymns of exultation,
Christ, your king and shepherd true:Bring him all the praise you know,
He is more than you bestow.
Never can you reach his due.Special theme for glad thanksgiving
Is the quick'ning and the living
Bread today before you set:From his hands of old partaken,
As we know, by faith unshaken,
Where the Twelve at supper met.Full and clear ring out your chanting,
Joy nor sweetest grace be wanting,
From your heart let praises burst:For today the feast is holden,
When the institution olden
Of that supper was rehearsed.Here the new law's new oblation,
By the new king's revelation,
Ends the form of ancient rite:Now the new the old effaces,
Truth away the shadow chases,
Light dispels the gloom of night.What he did at supper seated,
Christ ordained to be repeated,
His memorial ne'er to cease:And his rule for guidance taking,
Bread and wine we hallow, making
Thus our sacrifice of peace.This the truth each Christian learns,
Bread into his flesh he turns,
To his precious blood the wine:Sight has fail'd, nor thought conceives,
But a dauntless faith believes,
Resting on a pow'r divine.Here beneath these signs are hidden
Priceless things to sense forbidden;
Signs, not things are all we see:Blood is poured and flesh is broken,
Yet in either wondrous token
Christ entire we know to be.Whoso of this food partakes,
Does not rend the Lord nor breaks;
Christ is whole to all that taste:Thousands are, as one, receivers,
One, as thousands of believers,
Eats of him who cannot waste.Bad and good the feast are sharing,
Of what divers dooms preparing,
Endless death, or endless life.Life to these, to those damnation,
See how like participation
Is with unlike issues rife.When the sacrament is broken,
Doubt not, but believe 'tis spoken,
That each sever'd outward token
doth the very whole contain.Nought the precious gift divides,
Breaking but the sign betides
Jesus still the same abides,
still unbroken does remain.Lo! the angel's food is given
To the pilgrim who has striven;
see the children's bread from heaven,
which on dogs may not be spent.Truth the ancient types fulfilling,
Isaac bound, a victim willing,
Paschal lamb, its lifeblood spilling,
manna to the fathers sent.Very bread, good shepherd, tend us,
Jesu, of your love befriend us,
You refresh us, you defend us,
Your eternal goodness send us
In the land of life to see.You who all things can and know,
Who on earth such food bestow,
Grant us with your saints, though lowest,
Where the heav'nly feast you show,
Fellow heirs and guests to be. Amen. Alleluia.
