"On Preaching" from the Confessions (#21)

The question has been, Is the preaching of the Holy Gospel strictly speaking only a preaching of grace which proclaims the forgiveness of sins, or is it also a preaching of repentance and reproof that condemns unbelief, since unbelief is condemned not in the law but wholly through the Gospel? (Tappert, The Book of Concord. Fortress Press: Philadelphia, 1959, p.477-8; FC Epitome V: 1).
Answer? The Word of God must be rightly divided in order to maintain the distinction between Law and Gospel. Strictly speaking, the Law "teaches what is right and God-pleasing" and "condemns everything that is sinful and contrary to God's will" (ibid, 478:3). Strictly speaking, the Gospel "is the kind of doctrine that teaches what a man who has not kept the law and is condemned by it should believe, namely, that Christ has satisfied and paid for all guilt and without man’s merit has obtained and won for him forgiveness of sins, the 'righteousness that avails before God,' and eternal life" (ibid, 5; cf. 7).

However, the term 'Gospel' is not always used in its strict sense when it is used in Holy Scripture. The word may also mean "a proclamation both of repentance and of forgiveness of sins" (ibid, 6).