The following hangs in our Sacristy at Grace Lutheran, Racine:
Luther’s Sacristy Prayer
O Lord God, dear Father in heaven, I am indeed unworthy of the office and ministry in which I am to make known Thy glory and to nurture and to serve this congregation.
But since Thou hast appointed me to be a pastor and teacher, and the people are in need of the teachings and the instructions, O be Thou my helper and let Thy holy angels attend me.
Then if Thou art pleased to accomplish anything through me, to Thy glory and not to mine or to the praise of men, grant me, out of Thy pure grace and mercy a right understanding of Thy Word and that I may also diligently perform it.
O Lord Jesus Christ, Son of the living God, Thou Shepherd and Bishop of our souls, send Thy Holy Spirit that He may work with me, yea, that He may work in me to will and to do through Thy divine strength according to Thy good pleasure. Amen.
Here is another of Luther's sacristy prayers, from the ICL website:
Lord God, You have appointed me as a Bishop and Pastor in Your Church, but
you see how unsuited I am to meet so great and difficult a task. If I had
lacked Your help, I would have ruined everything long ago. Therefore, I
call upon You: I wish to devote my mouth and my heart to you; I shall
teach the people. I myself will learn and ponder diligently upon You Word.
Use me as Your instrument -- but do not forsake me, for if ever I should
be on my own, I would easily wreck it all.