Me? An Instrument of Righteousness?!?

Eph. 2:6 6 And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus,
Rom. 6:13 13 ...but rather offer yourselves to God as those who have been brought from death to life; and offer every part of yourself to him as an instrument of righteousness.

But I did not know I would do THIS sin!
I accepted forgiveness for all I had done,
and all that I should have but didn't achieve
And now I am shocked, find it hard to believe,
the grizzly, and gristly nature of this,
my latest act of miserableness.
I must reexamine the hope that I have:
I'm called God's child, and not sin's slave.
Can I still claim the forgiveness, still be that blessed thing,
An instrument of righteousness, serving the King?
Thanks be to God for the grace He extends,
forgiveness of all sins until this life ends.
Though I try not to fail Him I do anyway.
but He saw I would fail Him, saw all on that day
When He made me the offer to die in my place,
knowing full well the filth I would throw in His face.
And this sin, my latest in a long line of fault,
makes clear I cannot seem to bring it to a halt.
If I am forgiven, as night follows day
it follows all people are loved in this way.
Lord, sharpen this instrument, polish off rust,
to serve You and Your people until I am dust.

-HJ, April 2011