The genius of Christianity takes the words of Paul “who gave himself for our sins” as true and efficacious. We are not to look upon our sins as insignificant trifles. On the other hand, we are not to regard them as so terrible that we must despair. Learn to believe that Christ was given, not for picayune and imaginary transgressions, but for mountainous sins; not for one or two, but for all; not for sins that can be discarded, but for sins that are stubbornly ingrained
Practice this knowledge and fortify yourself against despair, particularly in the last hour, when the memory of past sins assails the conscience. Say with confidence: “Christ, the Son of God, was given not for the righteous, but for sinners. If I had no sin I should not need Christ. No, Satan, you cannot delude me into thinking I am holy. The truth is, I am all sin. My sins are not imaginary transgressions, but sins against the first table, unbelief, doubt, despair, contempt, hatred, ignorance of God, ingratitude towards Him, misuse of His name, neglect of His Word, etc.; and sins against the second table, dishonor of parents, disobedience of government, coveting of another’s possessions, etc. Granted that I have not committed murder, adultery, theft, and similar sins in deed, nevertheless I have committed them in the heart, and therefore I am a transgressor of all the commandments of God. “Because my transgressions are multiplied and my own efforts at self-justification rather a hindrance than a furtherance, therefore Christ the Son of God gave Himself into death for my sins.” To believe this is to have eternal life.
Let us equip ourselves against the accusations of Satan with this and similar passages of Holy Scripture. If he says, “Thou shalt be damned,” you tell him: “No, for I fly to Christ who gave Himself for my sins. In accusing me of being a damnable sinner, you are cutting your own throat, Satan. You are reminding me of God’s fatherly goodness toward me, that He so loved the world that He gave His only-begotten Son that whosoever believeth in Him should not perish, but have everlasting life. In calling me a sinner, Satan, you really comfort me above measure.” With such heavenly cunning we are to meet the devil’s craft and put from us the memory of sin.
source: http://www.ccel.org/ccel/luther/galatians.html
