This text comes from The Book of Scottish Song, edited by Alexander Whitelaw, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
O sweet is summer's scented breath,
When flowers bloom rich in muir and dell,
But sweeter far, and bonnier baith,
Is rosy-cheeked Isabell.
O my dear Isabell,
O my lovely Isabell,
Time may change, and hearts may range,
But still I'll love my Isabell.
O what to me were wealth or worth?
O what were blessed life itsel'?
Or what the joys and gems of earth,
Without the love of Isabell?
O my dear Isabell,
O my lovely Isabell,
She's a' to me that saint should be,
My joy and jewel Isabell.
I feel that poverty is bless'd,
It has mair joys than tongue can tell;
For were I rich, I'd ne'er possess'd
The bosom love of Isabell.
O my dear Isabell,
O my lovely Isabell,
I bless my lot, because it's got
My rosy-cheeked Isabell.