And Luther agrees, Luther writes that mortal sin and faith cannot coexist.
"On the other hand, if certain sectarists would arise, some of whom are perhaps already extant, and in the time of the insurrection [of the peasants] came to my own view, holding that all those who had once received the Spirit or the forgiveness of sins, or had become believers, even though they should afterwards sin, would still remain in the faith, and such sin would not harm them, and [hence] crying thus: “Do whatever you please; if you believe, it all amounts to nothing; faith blots out all sins,” etc.—they say, besides, that if any one sins after he has received faith and the Spirit, he never truly had the Spirit and faith: I have had before me [seen and heard] many such insane men, and I fear that in some such a devil is still remaining [hiding and dwelling].
It is, accordingly, necessary to know and to teach that when holy men, still having and feeling original sin, also daily repenting of and striving with it, happen to fall into manifest sins, as David into adultery, murder, and blasphemy, that then faith and the Holy Ghost has departed from them [they cast out faith and the Holy Ghost]. For the Holy Ghost does not permit sin to have dominion, to gain the upper hand so as to be accomplished, but represses and restrains it so that it must not do what it wishes. But if it does what it wishes, the Holy Ghost and faith are [certainly] not present. For St. John says, 1 John 3:9: Whosoever is born of God doth not commit sin, … and he cannot sin. And yet it is also the truth when the same St. John says, 1:8: If we say that we have no sin, we deceive ourselves and the truth is not in us."- The Smalcald Articles, Part III, Article III, 42-43
Luther is careful to maintain that the consolation of the Gospel does not excuse evil, and that mortal sin and faith cannot co-exist; that is why the Christian is called to that life of repentance. It is why both Law and Gospel are preached, and each preached rightly. It is the Law that condemns us in our sin, and drives us to our knees in grief, sorrow, and repentance that we should confess our sins; it is the Gospel that consoles the sinner, that he is justified, and that his sins are indeed forgiven.
We should neither fall into the pit of despair and hopelessness, by which on account of our sin we realize our uncalculable distance from God and His glorious holiness and justice; for here is only death.
Nor should we grow arrogant and proud, that we have "now made it", and thus we can live faithless lives of sin and death--this too is death.
Life is found in Jesus. Jesus who gives us His life as pure gift, and keeping us in Him, He holds us in faith. The Law holds us accountable, the Gospel keeps us safe. And so we confess our sins, with faith in God's grace and forgiveness in Christ. So that when we hear those sacramental words, "Your sins are forgiven", we can rest in the confidence of their truth--we are forgiven, God forgives us, Christ died for us.
We aren't pretending to be anything that we aren't, but we are in God's presence in Christ confessing our nakedness even as Christ clothes us with Himself. We are naked and ashamed, and yet we are garmented with Jesus Christ in the boldness of His Gospel. We therefore stand before God justified, beating our breast, saying, "Lord have mercy on me, a sinner". I, a sinner before God, dressed in Jesus with the full confidence of Jesus before His Father. In my shame I do not even gaze up into heaven, but in faith I hear the Gospel and lift my eyes to behold Jesus Christ with arms wide open on the cross, who brings me before God in glorious heaven in Himself.
We have been seated in heavenly places in Christ Jesus, who ascended and who sits and reigns at the right hand of the Father.
Even as we struggle and war between the old and the new man here on earth.
That's what we Lutherans mean when we talk about the paradox of the Simul, that we are simul iustus et peccator, both saint and sinner.
-CryptoLutheran