This poem is reputedly from Martin Luther although I cannot find a citation of where.

I do not come because my soul is free from sin and pure and whole and worthy of Thy grace;
I do not speak to Thee because I ever justly kept Thy laws and dare to meet Thy face.

I know that sin and guilt combine to reign o’er every thought of mine and turn from good to ill;
I know that when I try to be upright and just and true to Thee, I am a sinner still.

I know that often when I strive to keep a spark of love alive for Thee, the powers within
Leap up in unsubmissive might and oft benumb my sense of right and pull me back to sin.

I know that though in doing good I spend my life, I never could atone for all I’ve done;
But though my sins are black as night, I dare to come before Thy sight because I trust Thy Son.

In Him alone my trust I place, come boldly to Thy throne of grace, and there commune with Thee.
Salvation sure, O Lord, is mine, and, all Unworthy, I am Thine, for Jesus died for me.