I heard a choral setting of this poem at the Madison Choral Project concert I attended last Saturday (under the title "I know my soul hath power to know all things") and while I wasn't tremendously enthused by the song — I didn't think it fit the tone of the poem very well — I was quite tickled by the text.
I KNOW my soul hath power to know all things,
Yet she is blind and ignorant in all:
I know I'm one of Nature's little kings,
Yet to the least and vilest things am thrall.
I know my life's a pain and but a span;
I know my sense is mock'd in everything;
And, to conclude, I know myself a Man—
Which is a proud and yet a wretched thing.
Sir John Davies (1569–1626)
Here's the choral setting, so you can judge for yourself whether it suits the poem.