This text comes from Mediaeval Hymns and Sequences, edited by John Mason Neale, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
Alleluia! Alleluia! Alleluia!
Ye sons and daughters of the King
Whom heavenly hosts in glory sing,
To-day the grave hath lost its sting!
Alleluia.
On that first morning of the week,
Before the day began to break,
They went their buried Lord to seek.
Alleluia.
Both Mary, as it came to pass,
And Mary Magdalene it was,
And Mary, wife of Cleophas.
Alleluia.
An Angel clad in white was he
That sate and spake unto the three,
"Your Lord is gone to Galilee!"
Alleluia.
When John the Apostle heard the fame,
He to the tomb with Peter came:
But in the way outran the same.
Alleluia.
That night the Apostles met in fear:
Amidst them came their Lord most dear,
And said, "Peace be unto all here!"
Alleluia.
When Didymus had after heard
That Jesus had fulfilled His Word,
He doubted if it were the Lord.
Alleluia.
"Thomas, behold My Side," saith He;
"My Hands, My Feet, My Body see:
And doubt not, but believe in Me."
Alleluia!
No longer Didymus denied:
He saw the Hands, the Feet, the Side;
"Thou art my Lord and God," he cried.
Alleluia.
Blessed are they that have not seen,
And yet whose faith hath constant been:
In Life Eternal they shall reign.
Alleluia.
On this most holy Day of days,
Be laud and jubilee and praise:
To God both hearts and voices raise:
Alleluia.
And we with Holy Church unite,
As is both meet and just and right,
In glory to the King of Light.
Alleluia.