For example, how would you answer this question: "You don't even have to be sorry for your sins, you don't have to confess them, you don't have to do anything is that really what we are talking about with the Gospel of Jesus Christ?"
Precision of language is very important in any theological debate. What is sin? What is repentance? What is faith?
I submit that even most Lutheran pastors these days have an inadequate exposure to and memory of Lutheran theological terms. Ad fontes, fratres. Here is a standard Lutheran way of talking about repentance and faith from John Gerhard. It is from section 107 of his Theological Commonplaces volume On Justification. I'm currently editing the volume for CPH, and it's due for publication in 2018.
The article on the forgiveness of sins must be believed according to the interpretation of Scripture. But this shows that sins are forgiven to no one specifically unless he repents sincerely and embraces Christ in true faith. Therefore this precedes in the Creed: “I believe in Jesus Christ, the Son of God, etc., suffered and died,” etc. But now, people who sin willingly do not repent sincerely nor do they embrace Christ in true faith. They should not promise themselves remission of sins. Therefore they should be called not heretics but unbelievers and wicked persons.. For a heretic is a person who does not believe what he should believe, but someone who sins willingly should not believe that his sins are forgiven him so long as he is and remains the sort of person he is.
Now, what does it mean to "sin willingly?" Gerhard is talking about mortal sin as opposed to venial sin. Faith cannot exist with willful, mortal sin. Faith does not subsist without repentance.
If this way of speaking sounds odd to you, I would submit that it is because in our day and age we settle for slogans and not good, historic, careful, Lutheran theology.
Here is a sure way to get yourself on the right track in regard to this entire set of topics regarding Law and Gospel, Repentance and Faith: Chemnitz' Enchiridion. Clergy or lay, this is a must read, and an easy read, from the chief author of the Formula of Concord.