Pope Urban IV established the Feast of Corpus Christi. He requested St. Thomas Aquinas to compose hymns for it. Lauda Sion is one of the beautiful hymns Aquinas composed in honor of Jesus in the Blessed Sacrament. Each verse explains what Catholics believe about the Eucharist.
Sion, lift thy voice and sing:
Praise thy Savior and thy King;
Praise with hymns thy Shepherd true:
Dare thy most to praise Him well;
For He doth all praise excel;
None can ever reach His due.
Special theme of praise is thine,
That true living Bread divine,
That life-giving flesh adored,
Which the brethren twelve received,
As most faithfully believed,
At the Supper of the Lord.
Let the chant be loud and high;
Sweet and tranquil be the joy
Felt to-day in every breast;
On this festival divine
Which recounts the origin
Of the glorious Eucharist.
At this table of the King,
Our new Paschal offering
Brings to end the olden rite;
Here, for empty shadows fled,
Is reality instead;
Here, instead of darkness, light.
His own act, at supper seated,
Christ ordained to be repeated,
In His memory divine;
Wherefore now, with adoration,
We the Host of our salvation
Consecrate from bread and wine.
Hear what holy Church maintaineth,
That the bread its substance changeth
Into Flesh, the wine to Blood.
Doth it pass thy comprehending?
Faith, the law of sight transcending,
Leaps to things not understood.
Here in outward signs are hidden
Priceless things, to sense forbidden;
Signs, not things, are all we see:-
Flesh from bread, and Blood from wine;
Yet is Christ, in either sign,
All entire confessed to be.
They too who of Him partake
Sever not, nor rend, nor break,
But entire their Lord receive.
Whether one or thousands eat,
All receive the selfsame meat,
Nor the less for others leave.
Both the wicked and the good
Eat of this celestial Food;
But with ends how opposite!
Here ’tis life; and there ’tis death;
The same, yet issuing to each
In a difference infinite.
Nor a single doubt retain,
When they break the Host in twain,
But that in each part remains
What was in the whole before;
Since the simple sign alone
Suffers change in state or form,
The Signified remaining One
And the Same forevermore
Lo! upon the Altar lies,
Hidden deep from human eyes,
Angels’ Bread from Paradise
Made the food of mortal man:
Children’s meat to dogs denied;
In old types foresignified;
In the manna from the skies,
In Isaac, and the Paschal Lamb.
Jesu! Shepherd of the sheep!
Thy true flock in safety keep.
Living Bread! Thy life supply;
Strengthen us, or else we die;
Fill us with celestial grace:
Thou, who feedest us below!
Source of all we have or know!
Grant that with Thy Saints above,
Sitting at the Feast of Love,
We may see Thee face to face. Amen