In its proper sense, Gospel does not mean the preaching of repentance, but only the preaching of God's grace. This follows directly after the preaching of repentance, as Christ says, "Repent and believe in the gospel" (Mark 1:15).
Likewise the term repentance is not used in the Holy Scriptures in one and the same sense. In some passages of Holy Scripture it is used and taken to mean a person's entire conversion. For example, "Unless you repent, you will all likewise perish" (Luke 13:5). And, "There will be more joy in heaven over one sinner who repents" (Luke 15:7). But in this passage (Mark 1:15) and elsewhere, when repentance and faith in Christ (Acts 20:21), or repentance and forgiveness of sins, are mentioned as distinct, to repent means nothing other than to truly acknowledge sins, to be heartily sorry for them, and to stop doing them. This knowledge comes from the Law. It is not enough for saving conversion to God if faith in Christ is not added. The comforting preaching of the Holy Gospel offers His merits to all penitent sinners who are terrified by the preaching of the Law. The Gospel proclaims the forgiveness of sins, not to course and self-secure hearts, but to the bruised or penitent (Luke 4:18). The preaching of the Gospel must be added so that the repentance may lead to salvation and not to the Law's contrition or terrors. (paragraphs 6-9)
Condensed from CONCORDIA: THE LUTHERAN CONFESSIONS, copyright 2005,2006 by Concordia Publishing House. Used by permission. All rights reserved. To purchase a copy of CONCORDIA, call 800-325-3040.