I don't know what lyrics Celtic Thunder sing; I've only heard this small sample:

...knapsack all my wealth,
A poor but honest soldier.

[CHORUS?:] Oh, the deadly wars are blast and blown...

Those words don't exactly match anything I've found—and neither does their title THE DEADLY WARS—but they do seem to be derived from Burns' poem. The following text is much longer than the version in the DT, which contains only verses 1, 3, 6, and 7 of the original 8 verses.

I can understand wanting to shorten the song, especially if you sing it in the same slow tempo as Celtic Thunder, but in my opinion, verse 8 is the best and shouldn't be omitted.

From The Works of Robert Burns: With an Account of His Life, And a Criticism on His Writings, Volume 4 by Robert Burns (Liverpool: Printed by J. M'Creery, for T. Cadell, jun., and W. Davies, London; and W. Creech, Edinburgh, 1800), page 50:


WHEN WILD WAR'S DEADLY BLAST WAS BLAWN
Robert Burns
Air—"The Mill mill O."

1. When wild war's deadly blast was blawn,
And gentle peace returning,
Wi' mony a sweet babe fatherless,
And mony a widow mourning,
I left the lines and tented field,
Where lang I'd been a lodger,
My humble knapsack a' my wealth,
A poor and honest sodger.

2. A leal, light heart was in my breast,
My hand unstain'd wi' plunder;
And for fair Scotia, hame again,
I cheery on did wander.
I thought upon the banks o' Coil,
I thought upon my Nancy,
I thought upon the witching smile
That caught my youthful fancy:

3. At length I reach'd the bonny glen,
Where early life I sported;
I pass'd the mill, and trysting thorn,
Where Nancy aft I courted:
Wha spied I but my ain dear maid,
Down by her mother's dwelling!
And turn'd me round to hide the flood
That in my een was swelling.

4. Wi' alter'd voice, quoth I, sweet lass,
Sweet as yon hawthorn's blossom,
O! happy, happy may he be,
That's dearest to thy bosom:
My purse is light, I've far to gang,
And fain wad be thy lodger;
I've serv'd my king and country lang,
Take pity on a sodger.

5. Sae wistfully she gaz'd on me,
And lovelier was than ever;
Quo' she, a sodger ance I lo'ed,
Forget him shall I never;
Our humble cot, and hamely fare,
Ye freely shall partake it,
That gallant badge, the dear cockade,
Ye're welcome for the sake o't.

6. She gaz'd—she redden'd like a rose—
Syne pale like ony lily;
She sank within my arms and cried,
Art thou my ain dear Willie?
By him who made yon sun and sky—
By whom true love's regarded,
I am the man; and thus may still
True lovers be rewarded.

7. The wars are o'er, and I'm come hame,
And find thee still true-hearted;
Tho' poor in gear, we're rich in love,
And mair we'se ne'er be parted.
Quo' she, my grandsire left me gowd,
A mailin plenish'd fairly;
And come, my faithful sodger lad
Thou'rt welcome to it dearly!

8. For gold the merchant ploughs the main,
The farmer ploughs the manor;
But glory is the sodger's prize,
The sodger's wealth is honor;
The brave poor sodger ne'er despise,
Nor count him as a stranger.
Remember he's his country's stay
In day and hour of danger.