Doubtful Assurance is Not Humility

Here there may be a conflict. A person may feel and fear that he is not a child; he may imagine and feel that God is a Judge over him, angry and austere, as happened to Job and many others. But although filial confidence may tremble and quake in such a conflict, it must finally win; otherwise all is lost....

We, too, know well enough that we are poor sinners. But here the thing to do is not to look at what we are and do but at what Christ is and has done, and is still doing, for us. We are not speaking about our nature now but about the grace of God, which is as far above us as "the heaven is high above the earth" and as far "as the east is from the west" (Ps. 103:11-12). If you consider it a great matter to be a child of God, do not think it a small matter that the Son of God, born of a woman and made under the Law, came that you might become such a child.

Source: Quoted in Ewald M. Plass, What Luther Says, A Practical In-home Theology for the Active Christian. St. Louis: Concordia Publishing House. 1959 Edition, 10th Printing (1994), p. 428