What is repentance? Obviously the word has both a broad and narrow sense in the Sacred Scriptures, but there is no place where its narrow and proper definition is stated more clearly and succinctly than in Formula of Concord, Solid Declaration V:8:

But in this passage (Mark 1:15) and elsewhere, when repentance and faith in Christ, or repentance and the forgiveness of sins, are mentioned as distinct, to repent means nothing other than to truly acknowledge sins, to be heartily sorrow for them, and to stop doing them.

It’s the bald statement of that last item that I think is sorely lacking in our preaching of repentance these days. Bishop Bo Giertz, in his wonderful Hammer of God, I think in the second story, has the question put to the pastor: “How do I know if I’ve truly repented of a sin?” The answer the wise pastor gave was taken right from the Book of Concord: “Because you’ve stopped doing it.”

That’s not the answer our old Adam likes to hear at all! That old rascal imagines that he would happily consent to feel just DREADFUL about his sinfulness every day, provided he were only allowed to indulge it. We must recognize that repentance means laying down our arms in the world’s revolt against King Jesus. If He is our beloved King who has shed His blood that we might be His own, this is so that we might live under Him in His Kingdom and serve HIM in everlasting righteousness, innocence and blessedness. Clothed in Him and His forgiveness, we can no longer coddle our sinful behaviors. They are deadly. They are out to destroy us.

Because we have been made Christ’s soldiers, and are loyal to our King, we will line them up against the wall and execute them:“Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.”—Colossians 3:5 (ESV) Every single time they pop up, every single instance where they beg to live on in us, we take aim and fire. This is what we signed up for, after all: “And he said to all, ‘If anyone would come after me, let him deny himself and take up his cross daily and follow me.’”—Luke 9:23 (ESV)