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.
I've loved thee, love, lang, I've loved thee, love, deep;
I love thee awake, love, I love thee asleep;
While I think, while I feel, while I smile, while I weep,
By day, or by night, or in dream!
Though never by me, love, your praise has been sung,
Though never love told you were charming and young,
You dwell in my heart, love, and not on my tongue,
And there are you dweller supreme.
Great nature boasts not, love, the depth of her hoards,
The air never tells of the life it affords,
The sun gives its light, love, and utters no words;
Now sun and air surely are true.
My eyes cannot look, love, my lips cannot tell,
The tide of my heart in its ebb or its swell;
I cannot let others see how I love well,
Yet still do I worship but you.