“Upon this your confession”

"But when prior to the absolution we ask those desiring it whether they sincerely repent of their sins, believe in Jesus Christ, and have the good and earnest purpose henceforth to amend their sinful life, we do not mean to imply that the remission of sins is based on contrition, faith, and improvement of life… Our one aim in asking those questions before pronouncing absolution is not only to keep secure sinners from becoming fortified in their carnal security, but to console poor, brokenhearted sinners. Any other interpretation of our form of absolution would contradict the Gospel of grace and, instead of consoling burdened consciences, would drive them into the sea of doubt" (Pieper, Christian Dogmatics, volume 3, page 201).

See pages 199-207 for further discussion. The unconditional nature of evangelical absolution is what distinguishes it from the various Reformed gospels. Pieper was not exaggerating when he said, "… for the Reformed the gospel is not even the news of a remission, but merely a proclamation of the conditions under which man can secure for himself the remission of sins" (page 203).

Praying for the Spirit

And in order that we may come to Christ, the Holy Ghost works true faith through the hearing of the Word, as the apostle testifies when he says, Rom. 10:17: Faith cometh by hearing and hearing by the Word of God, [namely] when it is preached in its truth and purity. Therefore, whoever would be saved should not trouble or harass himself with thoughts concerning the secret counsel of God, as to whether he also is elected and ordained to eternal life, with which miserable Satan usually attacks and annoys godly hearts. But they should hear Christ [and look upon Him as the Book of Life in which is written the eternal election], who is the Book of Life and of God’s eternal election of all of God’s children to eternal life: He testifies to all men without distinction that it is God’s will that all men should come to Him who labor and are heavy laden with sin, in order that He may give them rest and save them, Matt. 11:28. According to this doctrine of His they should abstain from their sins, repent, believe His promise, and entirely trust in Him; and since we cannot do this by ourselves, of our own powers, the Holy Ghost desires to work these things, namely, repentance and faith, in us through the Word and Sacraments. And in order that we may attain this, persevere in it, and remain steadfast, we should implore God for His grace, which He has promised us in Holy Baptism, and, no doubt, He will impart it to us according to His promise, as He has said, Luke 11:11ff : If a son shall ask bread of any of you that is a father, will he give him a stone? Or if he ask a fish, will he for a fish give him a serpent? Or if he shall ask an egg, will he offer him a scorpion? If ye, then, being evil, know how to give good gifts unto your children, how much more shall your heavenly Father give the Holy Spirit to them that ask Him!
 
Formula Of Concord, Solid Declaration, Article XI, Paragraphs 69-71

Luther on objective justification

Some have asserted that the distinction between objective and subjective justification is a development of Lutheran theology that occurred only after the time of the Reformation. Martin Luther, however, had explicitly taught that all have been forgiven whether or not they believe it and yet that those who refuse to believe thereby forfeit the benefits of forgiveness:

Even he who does not believe that he is free and his sins forgiven shall also learn, in due time, how assuredly his sins were forgiven, even though he did not believe it. St. Paul says in Rom. 3[:3]: “Their faithlessness nullify the faithfulness of God.” We are not talking here either about people’s belief or disbelief regarding the efficacy of the keys. We realize that few believe. We are speaking of what the keys accomplish and give. He who does not accept what the keys give receives, of course, nothing. But this is not the key’s fault. Many do not believe the gospel, but this does not mean that the gospel is not true or effective. A king gives you a castle. If you do not accept it, then it is not the king’s fault, nor is he guilty of a lie. But you have deceived yourself and the fault is yours. The king certainly gave it.

Well, you say, here you yourself teach that the key fails. For the keys do not accomplish their purpose when some do not believe nor accept. Well, friend, if you call this failing, then God fails in all his words and works. For few accept what he constantly speaks and does for all. This means doing violence to the proper meaning of words. I do not call it a failure or a mistake if I say or do something, and somebody else despises or ignores it. But so they understand, teach, and observe concerning the pope’s wrong key: The key itself can err, even though a person would like to accept and rely on it. For it is a conditionalis clavis, a conditional, a vacillating key which does not direct us to God’s Word, but to our own repentance. It does not say candidly and boldly that you are to believe that I most certainly loose you. But it says that if you are repentant and pious, I loose you, if not, then I fail. That is the clavis errans, the erring key. It cannot with any assurance say that I know for certain that I have loosed you before God, whether you believe it or not, as St. Peter’s key can say.

Luther, M., The Keys (1999, c1958), Luther’s Works, vol. 40: Church and Ministry II (J. J. Pelikan, H. C. Oswald & H. T. Lehmann, Ed.), Philadelphia: Fortress Press, pp. 366-367, hyperlink added.

Until the first president of the Lutheran Church—Missouri Synod read that treatise, also called On the Keys, he did not understand the gospel of the kingdom (C. F. W. Walther, The Proper Distinction between Law and Gospel).

As he pointed out, the unconditional good news announced by Luther — that the Lamb of God takes away the sin of the world — is diametrically opposed to the conditional "gospels" taught by the denominations — that a sinner cannot have assurance of forgiveness without first either choosing Christ or determining whether one is among the few for whom he died. The schism arose because, not satisfied with the Agapē motif proclaimed by Luther in its simplicity, Calvin, Arminius, and others mixed in seemingly reasonable elements of the spiritual Erōs philosophy, the ancient Greek version of the lie that man must reach up to God. There is good news: God came down to rescue those who do not have the strength to make the right decision or to find evidence of their election (Rom. 5:6-8).

What is the unforgivable sin?

Blaspheming the work of the Spirit

Jesus announced the good news of the kingdom of God, that the Messiah had finally come to overcome the kingdom of Satan, who had held mankind in bondage to suffering and death. The Holy Spirit demonstrated God’s victory by healing diseases, raising the dead, and casting out demons by the word of Christ. While some received the work of the Spirit with joy, others knowingly and willingly spoke against his work:

Then one was brought to Him who was demon-possessed, blind and mute; and He healed him, so that the blind and mute man both spoke and saw. And all the multitudes were amazed and said, “Could this be the Son of David?” Now when the Pharisees heard it they said, “This fellow does not cast out demons except by Beelzebub, the ruler of the demons.” But Jesus knew their thoughts, and said to them: “Every kingdom divided against itself is brought to desolation, and every city or house divided against itself will not stand. If Satan casts out Satan, he is divided against himself. How then will his kingdom stand? And if I cast out demons by Beelzebub, by whom do your sons cast them out? Therefore they shall be your judges. But if I cast out demons by the Spirit of God, surely the kingdom of God has come upon you. Or how can one enter a strong man’s house and plunder his goods, unless he first binds the strong man? And then he will plunder his house. He who is not with Me is against Me, and he who does not gather with Me scatters abroad. “Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come. (Matt. 12:22-32, NKJV).

Why will these Pharisees never be forgiven? Is it because Christ did not offer them the life of the kingdom or because he did not love them enough to die for all their sins? (Calvinists tend to reason in this direction more than others.) No; rather, in rejecting the work of the Spirit through the word of their Messiah, they rejected the forgiveness that had been sincerely offered to them.

That Christ died even for their unforgivable sin is paradoxical but is clear from the doctrine of humanity’s fall through Adam’s sin: the unforgivable sin, like all actual sins, flows from the sinful nature inherited from Adam. The elect are no less sinful than those who commit the unforgivable sin. Christ atoned for the original sin of Adam (according to Romans 5) and thus for all actual sins proceeding from it.

Not every sin of unbelief or blasphemy is unforgivable. The unforgivable sin is not merely final unbelief or blasphemy against the person of the Holy Spirit, but also willing blasphemy against the work of Holy Spirit with full knowledge of doing so. For example, according to Acts, Paul washed away his sins in baptism, so he could not possibly have committed the unforgivable sin when, as an unbeliever, he forced Christians to blaspheme Christ. Also, he later said he had sinned in ignorance. By contrast, blasphemy against the Spirit is knowing and deliberate, as seen in the above case of those who accused Christ of casting out Satan by the power of Satan. May our merciful Lord keep us from that sin!

The nature of the blasphemy against the work of the Spirit is summarized by the Christian Cyclopedia’s entry on the unpardonable sin, especially the last paragraph:

"This sin is unpardonable, not because of any unwillingness in God, or because His mercy and Christ’s merits are not great enough, but because of the condition of him who commits it: he continues to the end (the action of his sin is linear, rather than punctiliar) in obdurate rejection of the Word of God, divine grace and mercy, and Christ’s merits; cf. 1 Jn 5:16. Augustine of Hippo calls it final impenitence. One who does not repent does not receive forgiveness; cf. Rv 2:22."
For a fuller explanation, see Pieper’s Christian Dogmatics, Volume 1, 571-577.
 

Without the assurance that Christ died even for the unforgivable sin, trusting him for forgiveness becomes impossible. For if you do not believe Christ died for all the sins of the world, then how do you know whether Christ died for all of your sins? How would you know you have never committed the unforgivable sin? Without the good news that he paid for everyone’s sins, you would have to examine yourself to make sure you have never spoken against the work of the Spirit. But if the Lamb of God really takes away the sins not just of believers but of the whole world (John 1; 1 John 2; 1 Timothy 2), you have the promise that God in Christ has already reconciled you to him:

All this is from God, who through Christ reconciled us to himself and gave us the ministry of reconciliation; that is, in Christ God was reconciling the world to himself, not counting their trespasses against them, and entrusting to us the message of reconciliation (2 Corinthians 5:18-19, ESV).
Believe that promise and live forever (John 3).