When darkness long has veil'd my mind,
And smiling day once more appears,
Then, my Redeemer, then I find
The folly of my doubts and fears.

Straight I upbraid my wandering heart,
And blush that I should ever be
Thus prone to act so base a part,
Or harbour one hard thought of Thee!

Oh! let me then at length be taught
What I am still so slow to learn,
That God is love, and changes not,
Nor knows the shadow of a turn.

Sweet truth, and easy to repeat!
But when my faith is sharply tried,
I find myself a learner yet,
Unskilful, weak, and apt to slide.

But, O my Lord, one look from Thee
Subdues the disobedient will,
Drives doubt and discontent away,
And Thy rebellious worm is still.

Thou art as ready to forgive
As I am ready to repine;
Thou, therefore, all the praise receive;
Be shame and self-abhorrence mine.

William Cowper

http://www.poemhunter.com/poem/olney-hymn-40-peace-after-a-storm/