From the Word
14 And he said, ‘The God of our fathers appointed you to know his will, to see the Just One and to hear a voice from his mouth; 15 for you will be a witness for him to all men of what you have seen and heard. 16 And now why do you wait? Rise and be baptized, and wash away your sins, calling on his name.’
Acts 22:14–16, RSV
The benefit of the Sacrament of Baptism is this, that therein God unites himself with you and becomes one with you in a gracious, comforting covenant. You desire, in accordance with the purpose and meaning of Baptism, to die from your sins and to be renewed on the last day, a hope inspired by the sacrament. On the strength of such desire on your part, God admits you to Baptism. The renewing work begins from that hour; he imparts to you his grace and Holy Spirit, and the Holy Spirit begins to kill the sin in your nature and to prepare the latter for death and for the resurrection on the last day.
You pledge yourself to remain in this state, and throughout your life, to the moment of death, to destroy sin more and more. God, accepting your pledge, exercises you during your whole life by imposing many good works, and not a few sufferings. Since such is your pledge to God, God in turn shows you grace and covenants with you that he will not impute to you the sins remaining in your nature after Baptism and will not regard them, nor condemn you on account of them. He is pleased with your effort to destroy sins and your desire to be rid of them. Though evil thoughts and desires may stir, though at times you sin and fall, yet if you arise and renew your covenant, your sins are forgiven by virtue of the covenant based upon the Sacrament of Baptism. If it were not for this covenant, every sin, however small, would condemn us. Hence there is no greater comfort on earth than Baptism, in which we pass under the jurisdiction of God’s grace and mercy.
Therefore one should not be terrified when he feels evil lust; when one’s thoughts and desires burn with passion; even when one falls from grace, still there is no ground for despair. But he should call to mind his baptism and joyfully comfort himself with the fact that God there covenanted to slay his sins and not to impute them unto condemnation, provided he refuses to consent to them and remain in them; provided he calls upon God for grace in order to make self-discipline possible; to battle against sin until released by death.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 385–86.