This text comes from The Scottish Minstrel (First Series), a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
Braw, brat lads on Yarrow braes,
Ye wander thro' the blooming heather:
But Yarrow braes, nor Ettrick shaws,
Can match the lads o' Galla water.
But there is ane, a secret ane,
Aboon them a' I lo'e him better,
An' I'll be his, and he'll be mine,
The bonnie lad o' Galla water.
Altho' his daddie was nae laird,
An' tho' I hae na meikle tocher,
Yet rich in kindest, truest love,
We'll tent our flocks by Galla water.
It ne'er was wealth, it ne'er was wealth,
That coft contentment, peace, or pleasure;
The bands and bliss o' mutual love,
O! that's the world's chiefest treasure.