In my "Folk Songs of England, Scotland & Ireland" it's:

The minstrel boy to the war is gone,
In the ranks of death, you'll find him;
His father's sword he has girded on,
And his wild harp slung behind him.

"Land of song, said the warrior bard,
"Tho' all the word betrays thee,
"One sword at least thy rights shall guard,
"One faithful heart shall praise thee."

The minstrel fell, but the foeman's chain
Could not bring his proud soul under;
The harp he loved ne'er spoke again,
For he tore its chords asunder,

And said, "No chain shall sully thee,
"Thou soul of love and brav'ry!
"Thy songs were made for the pure and free,
"They ne'er shall sound in Slavery!"

Hope this helps Mert