Enter not into judgment with Your servant, for no one living is righteous before You.
I am very frequently troubled by this trial, that I look about for works in which I may be able to put my trust, because I have taught much, have benefited many, and have borne many more indignities than I deserved. But I realize that in real conflicts all these are nothing, and I am driven to the well-known confession of David, who said: "Lord, I am nothing but a sinner" (cf. Psalm 32:5); and (Psalm 116:11): "I said in my consternation: 'All men are a vain hope'"; that is, every man who deceives and is deceived is useless. Likewise (Psalm 143:2): "Enter not into judgment with Thy servant." But I encourage myself with this hope alone, that in the Gospel I see that solace has been promised to the contrite, hope to the despairing, and heaven to those who have been put into hell; and the fact that the Son of God, without our knowledge, offered Himself for us to God the Father, His Father, on the altar of the cross, is sure proof of this hope. . . . Therefore when you feel that you are being humbled, cast yourself at the feet of your heavenly Father and say: "O Lord, if Thou dealest with me in this manner, I shall bear it patiently, and I confess that I have deserved something more terrible. Therefore be merciful to me. . .. Thou dost not owe me a thing by any right. Therefore I cling to Thy mercy." This is the true way by which we come to grace and salvation.
From Lectures on Genesis (Luther's Works 4:54-55)